diff --git a/app-ios/Sources/ContributorFeature/ContributorView.swift b/app-ios/Sources/ContributorFeature/ContributorView.swift
index 9fb614844..6a6859db6 100644
--- a/app-ios/Sources/ContributorFeature/ContributorView.swift
+++ b/app-ios/Sources/ContributorFeature/ContributorView.swift
@@ -29,6 +29,7 @@ public let contributorReducer = Reducer<ContributorState, ContributorAction, Con
     switch action {
     case .refresh:
         return .run { @MainActor subscriber in
+            try await environment.contributorsRepository.refresh()
             for try await result: [Contributor] in environment.contributorsRepository.contributors().stream() {
                 await subscriber.send(
                     .refreshResponse(
diff --git a/app-ios/Sources/SponsorFeature/SponsorView.swift b/app-ios/Sources/SponsorFeature/SponsorView.swift
index 7e852be88..4bbbdc7b2 100644
--- a/app-ios/Sources/SponsorFeature/SponsorView.swift
+++ b/app-ios/Sources/SponsorFeature/SponsorView.swift
@@ -47,6 +47,7 @@ public let sponsorReducer = Reducer<SponsorState, SponsorAction, SponsorEnvironm
     case .refresh:
         state.isLoading = true
         return .run { @MainActor subscriber in
+            try await environment.sponsorsRepository.refresh()
             for try await result: [Sponsor] in environment.sponsorsRepository.sponsors().stream() {
                 await subscriber.send(
                     .refreshResponse(
diff --git a/app-ios/Sources/StaffFeature/StaffView.swift b/app-ios/Sources/StaffFeature/StaffView.swift
index 4e12eca89..743efe4c8 100644
--- a/app-ios/Sources/StaffFeature/StaffView.swift
+++ b/app-ios/Sources/StaffFeature/StaffView.swift
@@ -32,6 +32,7 @@ public let staffReducer = Reducer<StaffState, StaffAction, StaffEnvironment> { s
     switch action {
     case .refresh:
         return .run { @MainActor subscriber in
+            try await environment.staffRepository.refresh()
             for try await result: [Staff] in environment.staffRepository.staff().stream() {
                 await subscriber.send(
                     .refreshResponse(
diff --git a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/contributors/DataContributorsRepository.kt b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/contributors/DataContributorsRepository.kt
index 87d77f3d0..de88be1ec 100644
--- a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/contributors/DataContributorsRepository.kt
+++ b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/contributors/DataContributorsRepository.kt
@@ -3,27 +3,30 @@ package io.github.droidkaigi.confsched2022.data.contributors
 import io.github.droidkaigi.confsched2022.model.Contributor
 import io.github.droidkaigi.confsched2022.model.ContributorsRepository
 import kotlinx.collections.immutable.PersistentList
+import kotlinx.collections.immutable.persistentListOf
 import kotlinx.collections.immutable.toPersistentList
-import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.callbackFlow
 
 // TODO: Move to core-testing, once contributors server is created
 public class DataContributorsRepository(
     private val contributorsApi: ContributorsApi,
 ) : ContributorsRepository {
+    private val contributorsStateFlow =
+        MutableStateFlow<PersistentList<Contributor>>(persistentListOf())
+
     override fun contributors(): Flow<PersistentList<Contributor>> {
         return callbackFlow {
-            send(
-                contributorsApi
-                    .contributors()
-                    .toPersistentList()
-            )
-            awaitClose { }
+            contributorsStateFlow.collect {
+                send(it)
+            }
         }
     }
 
     override suspend fun refresh() {
-        TODO("Not yet implemented")
+        contributorsStateFlow.value = contributorsApi
+            .contributors()
+            .toPersistentList()
     }
 }
diff --git a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/contributors/FakeContributorsRepository.kt b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/contributors/FakeContributorsRepository.kt
index 4b6b33579..9824f1236 100644
--- a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/contributors/FakeContributorsRepository.kt
+++ b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/contributors/FakeContributorsRepository.kt
@@ -14,6 +14,5 @@ public class FakeContributorsRepository : ContributorsRepository {
     }
 
     override suspend fun refresh() {
-        TODO("Not yet implemented")
     }
 }
diff --git a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/sponsors/DataSponsorsRepository.kt b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/sponsors/DataSponsorsRepository.kt
index f0acea5a1..a95e36be9 100644
--- a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/sponsors/DataSponsorsRepository.kt
+++ b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/sponsors/DataSponsorsRepository.kt
@@ -3,18 +3,25 @@ package io.github.droidkaigi.confsched2022.data.sponsors
 import io.github.droidkaigi.confsched2022.model.Sponsor
 import io.github.droidkaigi.confsched2022.model.SponsorsRepository
 import kotlinx.collections.immutable.PersistentList
-import kotlinx.coroutines.channels.awaitClose
+import kotlinx.collections.immutable.persistentListOf
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.callbackFlow
 
 public class DataSponsorsRepository(
     private val sponsorsApi: SponsorsApi
 ) : SponsorsRepository {
+    private val sponsorsStateFlow =
+        MutableStateFlow<PersistentList<Sponsor>>(persistentListOf())
     override fun sponsors(): Flow<PersistentList<Sponsor>> =
         callbackFlow {
-            send(
-                sponsorsApi.sponsors()
-            )
-            awaitClose { }
+            sponsorsStateFlow.collect {
+                send(it)
+            }
         }
+
+    override suspend fun refresh() {
+        sponsorsStateFlow.value = sponsorsApi
+            .sponsors()
+    }
 }
diff --git a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/sponsors/FakeSponsorsRepository.kt b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/sponsors/FakeSponsorsRepository.kt
index 6ef626c98..02655f1dd 100644
--- a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/sponsors/FakeSponsorsRepository.kt
+++ b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/sponsors/FakeSponsorsRepository.kt
@@ -9,4 +9,7 @@ import kotlinx.coroutines.flow.flowOf
 
 public class FakeSponsorsRepository : SponsorsRepository {
     override fun sponsors(): Flow<PersistentList<Sponsor>> = flowOf(Sponsor.fakes())
+
+    override suspend fun refresh() {
+    }
 }
diff --git a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/staff/DataStaffRepository.kt b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/staff/DataStaffRepository.kt
index 3a3d37499..b45bdaa07 100644
--- a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/staff/DataStaffRepository.kt
+++ b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/staff/DataStaffRepository.kt
@@ -3,22 +3,29 @@ package io.github.droidkaigi.confsched2022.data.staff
 import io.github.droidkaigi.confsched2022.model.Staff
 import io.github.droidkaigi.confsched2022.model.StaffRepository
 import kotlinx.collections.immutable.PersistentList
+import kotlinx.collections.immutable.persistentListOf
 import kotlinx.collections.immutable.toPersistentList
-import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.callbackFlow
 
 public class DataStaffRepository(
     private val staffApi: StaffApi
 ) : StaffRepository {
+    private val staffStateFlow =
+        MutableStateFlow<PersistentList<Staff>>(persistentListOf())
+
     override fun staff(): Flow<PersistentList<Staff>> {
         return callbackFlow {
-            send(
-                staffApi
-                    .staff()
-                    .toPersistentList()
-            )
-            awaitClose { }
+            staffStateFlow.collect {
+                send(it)
+            }
         }
     }
+
+    override suspend fun refresh() {
+        staffStateFlow.value = staffApi
+            .staff()
+            .toPersistentList()
+    }
 }
diff --git a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/staff/FakeStaffRepository.kt b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/staff/FakeStaffRepository.kt
index dffaff3fc..d40e85ee9 100644
--- a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/staff/FakeStaffRepository.kt
+++ b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/data/staff/FakeStaffRepository.kt
@@ -12,4 +12,7 @@ public class FakeStaffRepository : StaffRepository {
     override fun staff(): Flow<PersistentList<Staff>> {
         return flowOf(staff)
     }
+
+    override suspend fun refresh() {
+    }
 }
diff --git a/core/model/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/model/SponsorsRepository.kt b/core/model/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/model/SponsorsRepository.kt
index 1fc95c359..238451e36 100644
--- a/core/model/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/model/SponsorsRepository.kt
+++ b/core/model/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/model/SponsorsRepository.kt
@@ -5,4 +5,6 @@ import kotlinx.coroutines.flow.Flow
 
 public interface SponsorsRepository {
     public fun sponsors(): Flow<PersistentList<Sponsor>>
+
+    public suspend fun refresh()
 }
diff --git a/core/model/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/model/StaffRepository.kt b/core/model/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/model/StaffRepository.kt
index 8e11285d3..d08e13a03 100644
--- a/core/model/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/model/StaffRepository.kt
+++ b/core/model/src/commonMain/kotlin/io/github/droidkaigi/confsched2022/model/StaffRepository.kt
@@ -5,4 +5,6 @@ import kotlinx.coroutines.flow.Flow
 
 public interface StaffRepository {
     public fun staff(): Flow<PersistentList<Staff>>
+
+    public suspend fun refresh()
 }
diff --git a/core/ui/src/main/java/io/github/droidkaigi/confsched2022/feature/announcement/AppErrorSnackbarEffect.kt b/core/ui/src/main/java/io/github/droidkaigi/confsched2022/feature/common/AppErrorSnackbarEffect.kt
similarity index 94%
rename from core/ui/src/main/java/io/github/droidkaigi/confsched2022/feature/announcement/AppErrorSnackbarEffect.kt
rename to core/ui/src/main/java/io/github/droidkaigi/confsched2022/feature/common/AppErrorSnackbarEffect.kt
index 3d097df68..541924d60 100644
--- a/core/ui/src/main/java/io/github/droidkaigi/confsched2022/feature/announcement/AppErrorSnackbarEffect.kt
+++ b/core/ui/src/main/java/io/github/droidkaigi/confsched2022/feature/common/AppErrorSnackbarEffect.kt
@@ -1,4 +1,4 @@
-package io.github.droidkaigi.confsched2022.feature.announcement
+package io.github.droidkaigi.confsched2022.feature.common
 
 import androidx.compose.material3.SnackbarDuration.Long
 import androidx.compose.material3.SnackbarHostState
diff --git a/feature/announcement/src/main/java/io/github/droidkaigi/confsched2022/feature/announcement/Announcements.kt b/feature/announcement/src/main/java/io/github/droidkaigi/confsched2022/feature/announcement/Announcements.kt
index f16bea6e1..631ea8daa 100644
--- a/feature/announcement/src/main/java/io/github/droidkaigi/confsched2022/feature/announcement/Announcements.kt
+++ b/feature/announcement/src/main/java/io/github/droidkaigi/confsched2022/feature/announcement/Announcements.kt
@@ -40,6 +40,7 @@ import io.github.droidkaigi.confsched2022.designsystem.components.KaigiScaffold
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiTopAppBar
 import io.github.droidkaigi.confsched2022.designsystem.theme.KaigiColors
 import io.github.droidkaigi.confsched2022.designsystem.theme.KaigiTheme
+import io.github.droidkaigi.confsched2022.feature.common.AppErrorSnackbarEffect
 import io.github.droidkaigi.confsched2022.model.AnnouncementsByDate
 import io.github.droidkaigi.confsched2022.model.fakes
 import io.github.droidkaigi.confsched2022.strings.Strings
diff --git a/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/Contributors.kt b/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/Contributors.kt
index 082af67d7..a1517c0c3 100644
--- a/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/Contributors.kt
+++ b/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/Contributors.kt
@@ -7,9 +7,11 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.Preview
@@ -19,6 +21,7 @@ import io.github.droidkaigi.confsched2022.designsystem.components.KaigiScaffold
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiTopAppBar
 import io.github.droidkaigi.confsched2022.designsystem.components.UsernameRow
 import io.github.droidkaigi.confsched2022.designsystem.theme.KaigiTheme
+import io.github.droidkaigi.confsched2022.feature.common.AppErrorSnackbarEffect
 import io.github.droidkaigi.confsched2022.model.Contributor
 import io.github.droidkaigi.confsched2022.model.fakes
 import io.github.droidkaigi.confsched2022.strings.Strings
@@ -38,6 +41,8 @@ fun ContributorsScreenRoot(
         uiModel = uiModel,
         showNavigationIcon = showNavigationIcon,
         onNavigationIconClick = onNavigationIconClick,
+        onRetryButtonClick = { viewModel.onRetryButtonClick() },
+        onAppErrorNotified = { viewModel.onAppErrorNotified() },
         onLinkClick = onLinkClick
     )
 }
@@ -47,10 +52,15 @@ fun Contributors(
     uiModel: ContributorsUiModel,
     showNavigationIcon: Boolean,
     onNavigationIconClick: () -> Unit,
+    onRetryButtonClick: () -> Unit,
+    onAppErrorNotified: () -> Unit,
     onLinkClick: (url: String, packageName: String?) -> Unit,
     modifier: Modifier = Modifier,
 ) {
+    val snackbarHostState = remember { SnackbarHostState() }
+
     KaigiScaffold(
+        snackbarHostState = snackbarHostState,
         modifier = modifier,
         topBar = {
             KaigiTopAppBar(
@@ -64,9 +74,17 @@ fun Contributors(
             )
         }
     ) { innerPadding ->
+        AppErrorSnackbarEffect(
+            appError = uiModel.appError,
+            snackBarHostState = snackbarHostState,
+            onAppErrorNotified = onAppErrorNotified,
+            onRetryButtonClick = onRetryButtonClick
+        )
         Box {
             when (uiModel.state) {
-                is Error -> TODO()
+                is Error -> {
+                    // Do nothing
+                }
                 Loading -> Box(
                     modifier = Modifier.padding(innerPadding).fillMaxSize(),
                     contentAlignment = Alignment.Center,
@@ -103,10 +121,13 @@ fun ContributorsPreview() {
             uiModel = ContributorsUiModel(
                 state = Success(
                     Contributor.fakes()
-                )
+                ),
+                appError = null,
             ),
             showNavigationIcon = true,
             onNavigationIconClick = {},
+            onRetryButtonClick = {},
+            onAppErrorNotified = {},
             onLinkClick = { _, _ -> },
         )
     }
diff --git a/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/ContributorsUiModel.kt b/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/ContributorsUiModel.kt
index a07ddd2d7..6d167e09d 100644
--- a/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/ContributorsUiModel.kt
+++ b/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/ContributorsUiModel.kt
@@ -1,7 +1,11 @@
 package io.github.droidkaigi.confsched2022.feature.contributors
 
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.Contributor
 import io.github.droidkaigi.confsched2022.ui.UiLoadState
 import kotlinx.collections.immutable.PersistentList
 
-data class ContributorsUiModel(val state: UiLoadState<PersistentList<Contributor>>)
+data class ContributorsUiModel(
+    val state: UiLoadState<PersistentList<Contributor>>,
+    val appError: AppError?
+)
diff --git a/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/ContributorsViewModel.kt b/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/ContributorsViewModel.kt
index 86aab043a..0460b5045 100644
--- a/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/ContributorsViewModel.kt
+++ b/feature/contributors/src/main/java/io/github/droidkaigi/confsched2022/feature/contributors/ContributorsViewModel.kt
@@ -3,33 +3,64 @@ package io.github.droidkaigi.confsched2022.feature.contributors
 import androidx.compose.runtime.State
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import app.cash.molecule.AndroidUiDispatcher
 import app.cash.molecule.RecompositionClock.ContextClock
 import dagger.hilt.android.lifecycle.HiltViewModel
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.ContributorsRepository
 import io.github.droidkaigi.confsched2022.ui.UiLoadState
 import io.github.droidkaigi.confsched2022.ui.asLoadState
 import io.github.droidkaigi.confsched2022.ui.moleculeComposeState
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class ContributorsViewModel @Inject constructor(
-    contributorsRepository: ContributorsRepository,
+    private val contributorsRepository: ContributorsRepository,
 ) : ViewModel() {
     private val moleculeScope =
         CoroutineScope(viewModelScope.coroutineContext + AndroidUiDispatcher.Main)
 
-    val uiModel: State<ContributorsUiModel>
+    private val contributorsFlow = contributorsRepository
+        .contributors()
+        .asLoadState()
+
+    private var appError by mutableStateOf<AppError?>(null)
+
+    val uiModel: State<ContributorsUiModel> = moleculeScope.moleculeComposeState(
+        clock = ContextClock
+    ) {
+        val contributorLoadState by contributorsFlow.collectAsState(initial = UiLoadState.Loading)
+        ContributorsUiModel(
+            state = contributorLoadState,
+            appError = appError
+        )
+    }
 
     init {
-        val dataFlow = contributorsRepository.contributors().asLoadState()
+        refresh()
+    }
 
-        uiModel = moleculeScope.moleculeComposeState(clock = ContextClock) {
-            val data by dataFlow.collectAsState(initial = UiLoadState.Loading)
-            ContributorsUiModel(data)
+    fun onRetryButtonClick() {
+        refresh()
+    }
+
+    private fun refresh() {
+        viewModelScope.launch {
+            try {
+                contributorsRepository.refresh()
+            } catch (e: AppError) {
+                appError = e
+            }
         }
     }
+
+    fun onAppErrorNotified() {
+        appError = null
+    }
 }
diff --git a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/Search.kt b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/Search.kt
index 3e7ff0b99..c6f1d90cd 100644
--- a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/Search.kt
+++ b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/Search.kt
@@ -36,6 +36,7 @@ import androidx.compose.material3.Divider
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextFieldDefaults
 import androidx.compose.material3.TopAppBar
@@ -70,6 +71,7 @@ import dev.icerock.moko.resources.compose.stringResource
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiScaffold
 import io.github.droidkaigi.confsched2022.designsystem.theme.KaigiTheme
 import io.github.droidkaigi.confsched2022.designsystem.theme.Typography
+import io.github.droidkaigi.confsched2022.feature.common.AppErrorSnackbarEffect
 import io.github.droidkaigi.confsched2022.model.DroidKaigi2022Day
 import io.github.droidkaigi.confsched2022.model.DroidKaigiSchedule
 import io.github.droidkaigi.confsched2022.model.Filters
@@ -167,6 +169,8 @@ fun SearchRoot(
                 viewModel.onFilterFavoritesToggle()
             },
             onBackIconClick = onBackIconClick,
+            onRetryButtonClick = { viewModel.onRetryButtonClick() },
+            onAppErrorNotified = { viewModel.onAppErrorNotified() },
             onSearchTextAreaClicked = {
                 viewModel.onSearchTextAreaClicked()
             }
@@ -184,10 +188,15 @@ private fun SearchScreen(
     onFavoritesToggleClicked: () -> Unit,
     onSearchTextAreaClicked: () -> Unit,
     onBackIconClick: () -> Unit,
+    onRetryButtonClick: () -> Unit,
+    onAppErrorNotified: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
     val searchWord = rememberSaveable { mutableStateOf("") }
+    val snackbarHostState = remember { SnackbarHostState() }
+
     KaigiScaffold(
+        snackbarHostState = snackbarHostState,
         modifier = modifier,
         topBar = {
             if (uiModel.state is Success) {
@@ -200,11 +209,19 @@ private fun SearchScreen(
             }
         },
         content = {
+            AppErrorSnackbarEffect(
+                appError = uiModel.appError,
+                snackBarHostState = snackbarHostState,
+                onAppErrorNotified = onAppErrorNotified,
+                onRetryButtonClick = onRetryButtonClick
+            )
             Column(
                 modifier = Modifier.padding(paddingValues = it)
             ) {
                 when (uiModel.state) {
-                    is Error -> TODO()
+                    is Error -> {
+                        // Do nothing
+                    }
                     is Success -> {
                         SearchFilter(
                             modifier = Modifier
@@ -545,7 +562,8 @@ fun SearchScreenPreview() {
             uiModel = SearchUiModel(
                 filter = SearchFilterUiModel(),
                 filterSheetState = SearchFilterSheetState.Hide,
-                state = Success(DroidKaigiSchedule.fake())
+                state = Success(DroidKaigiSchedule.fake()),
+                appError = null,
             ),
             onItemClick = {},
             onBookMarkClick = { _, _ -> },
@@ -553,6 +571,8 @@ fun SearchScreenPreview() {
             onFavoritesToggleClicked = {},
             onDayFilterClicked = {},
             onCategoriesFilteredClicked = {},
+            onRetryButtonClick = {},
+            onAppErrorNotified = {},
             onSearchTextAreaClicked = {},
         )
     }
@@ -566,7 +586,8 @@ fun SearchEmptyScreenPreview() {
             uiModel = SearchUiModel(
                 filter = SearchFilterUiModel(),
                 filterSheetState = SearchFilterSheetState.Hide,
-                state = Success(DroidKaigiSchedule.empty())
+                state = Success(DroidKaigiSchedule.empty()),
+                appError = null,
             ),
             onItemClick = {},
             onBookMarkClick = { _, _ -> },
@@ -575,6 +596,8 @@ fun SearchEmptyScreenPreview() {
             onDayFilterClicked = {},
             onCategoriesFilteredClicked = {},
             onSearchTextAreaClicked = {},
+            onAppErrorNotified = {},
+            onRetryButtonClick = {}
         )
     }
 }
diff --git a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SearchUiModel.kt b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SearchUiModel.kt
index efee70234..9e1c0c284 100644
--- a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SearchUiModel.kt
+++ b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SearchUiModel.kt
@@ -1,5 +1,6 @@
 package io.github.droidkaigi.confsched2022.feature.sessions
 
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.DroidKaigi2022Day
 import io.github.droidkaigi.confsched2022.model.DroidKaigiSchedule
 import io.github.droidkaigi.confsched2022.model.TimetableCategory
@@ -8,7 +9,8 @@ import io.github.droidkaigi.confsched2022.ui.UiLoadState
 data class SearchUiModel(
     val filter: SearchFilterUiModel,
     val filterSheetState: SearchFilterSheetState,
-    val state: UiLoadState<DroidKaigiSchedule>
+    val state: UiLoadState<DroidKaigiSchedule>,
+    val appError: AppError?
 )
 
 data class SearchFilterUiModel(
diff --git a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SearchViewModel.kt b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SearchViewModel.kt
index e909e0c49..5278609d9 100644
--- a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SearchViewModel.kt
+++ b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SearchViewModel.kt
@@ -6,12 +6,14 @@ import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import app.cash.molecule.AndroidUiDispatcher
 import app.cash.molecule.RecompositionClock.ContextClock
 import co.touchlab.kermit.Logger
 import dagger.hilt.android.lifecycle.HiltViewModel
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.DroidKaigi2022Day
 import io.github.droidkaigi.confsched2022.model.Filters
 import io.github.droidkaigi.confsched2022.model.SessionsRepository
@@ -32,18 +34,17 @@ class SearchViewModel @Inject constructor(
     private val sessionsRepository: SessionsRepository,
     sessionsZipline: SessionsZipline
 ) : ViewModel() {
-    private val moleculeScope =
-        CoroutineScope(viewModelScope.coroutineContext + AndroidUiDispatcher.Main)
-
-    val uiModel: State<SearchUiModel>
-
     private val filters = mutableStateOf(Filters())
 
     private val filterSheetState = mutableStateOf<SearchFilterSheetState>(
         SearchFilterSheetState.Hide
     )
+    private var appError by mutableStateOf<AppError?>(null)
+
+    val uiModel: State<SearchUiModel> = run {
+        val moleculeScope =
+            CoroutineScope(viewModelScope.coroutineContext + AndroidUiDispatcher.Main)
 
-    init {
         val ziplineScheduleModifierFlow = sessionsZipline.timetableModifier()
         val sessionScheduleFlow = sessionsRepository.droidKaigiScheduleFlow()
 
@@ -59,10 +60,8 @@ class SearchViewModel @Inject constructor(
                 schedule
             }
         }.asLoadState()
-
-        uiModel = moleculeScope.moleculeComposeState(clock = ContextClock) {
+        moleculeScope.moleculeComposeState(clock = ContextClock) {
             val schedule by scheduleFlow.collectAsState(initial = UiLoadState.Loading)
-
             val filteredSchedule by remember(filters) {
                 derivedStateOf {
                     schedule.mapSuccess { it.filtered(filters.value) }
@@ -76,7 +75,8 @@ class SearchViewModel @Inject constructor(
                     isFavoritesOn = filters.value.filterFavorite
                 ),
                 filterSheetState = filterSheetState.value,
-                state = filteredSchedule
+                state = filteredSchedule,
+                appError = appError,
             )
         }
     }
@@ -142,4 +142,26 @@ class SearchViewModel @Inject constructor(
     fun onSearchTextAreaClicked() {
         onFilterSheetDismissed()
     }
+
+    init {
+        refresh()
+    }
+
+    fun onRetryButtonClick() {
+        refresh()
+    }
+
+    private fun refresh() {
+        viewModelScope.launch {
+            try {
+                sessionsRepository.refresh()
+            } catch (e: AppError) {
+                appError = e
+            }
+        }
+    }
+
+    fun onAppErrorNotified() {
+        appError = null
+    }
 }
diff --git a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetail.kt b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetail.kt
index 58f10b4e5..ee7aba936 100644
--- a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetail.kt
+++ b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetail.kt
@@ -24,6 +24,7 @@ import androidx.compose.material3.FloatingActionButtonDefaults
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBar
 import androidx.compose.material3.TopAppBarDefaults
@@ -59,6 +60,7 @@ import io.github.droidkaigi.confsched2022.designsystem.components.KaigiScaffold
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiTag
 import io.github.droidkaigi.confsched2022.designsystem.theme.KaigiTheme
 import io.github.droidkaigi.confsched2022.designsystem.theme.TimetableItemColor
+import io.github.droidkaigi.confsched2022.feature.common.AppErrorSnackbarEffect
 import io.github.droidkaigi.confsched2022.model.KaigiPlace.Prism
 import io.github.droidkaigi.confsched2022.model.Lang
 import io.github.droidkaigi.confsched2022.model.MultiLangText
@@ -95,6 +97,8 @@ fun SessionDetailScreenRoot(
     SessionDetailScreen(
         modifier = modifier,
         uiModel = uiModel,
+        onRetryButtonClick = { viewModel.onRetryButtonClick() },
+        onAppErrorNotified = { viewModel.onAppErrorNotified() },
         onBackIconClick = onBackIconClick,
         onFavoriteClick = { currentFavorite ->
             viewModel.onFavoriteToggle(timetableItemId, currentFavorite)
@@ -134,6 +138,8 @@ fun SessionDetailTopAppBar(
 @Composable
 fun SessionDetailScreen(
     uiModel: SessionDetailUiModel,
+    onRetryButtonClick: () -> Unit,
+    onAppErrorNotified: () -> Unit,
     modifier: Modifier = Modifier,
     onBackIconClick: () -> Unit = {},
     onFavoriteClick: (Boolean) -> Unit = {},
@@ -141,10 +147,11 @@ fun SessionDetailScreen(
     onNavigateFloorMapClick: () -> Unit = {},
     onRegisterCalendarClick: (TimetableItem) -> Unit = {},
 ) {
-
     val uiState = uiModel.state
+    val snackbarHostState = remember { SnackbarHostState() }
 
     KaigiScaffold(
+        snackbarHostState = snackbarHostState,
         topBar = {
             SessionDetailTopAppBar(
                 onBackIconClick = onBackIconClick,
@@ -165,9 +172,17 @@ fun SessionDetailScreen(
             }
         },
     ) { innerPadding ->
+        AppErrorSnackbarEffect(
+            appError = uiModel.appError,
+            snackBarHostState = snackbarHostState,
+            onAppErrorNotified = onAppErrorNotified,
+            onRetryButtonClick = onRetryButtonClick
+        )
         Box(modifier = Modifier.padding(innerPadding)) {
             when (uiState) {
-                is Error -> TODO()
+                is Error -> {
+                    // Do nothing
+                }
                 Loading ->
                     Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
                         CircularProgressIndicator()
@@ -624,8 +639,11 @@ fun PreviewSessionDetailScreen() {
     KaigiTheme {
         SessionDetailScreen(
             uiModel = SessionDetailUiModel(
-                Success(TimetableItemWithFavorite.fake())
-            )
+                state = Success(TimetableItemWithFavorite.fake()),
+                appError = null,
+            ),
+            onRetryButtonClick = {},
+            onAppErrorNotified = {},
         )
     }
 }
diff --git a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetailUiModel.kt b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetailUiModel.kt
index 2d4362791..91987c209 100644
--- a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetailUiModel.kt
+++ b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetailUiModel.kt
@@ -1,6 +1,10 @@
 package io.github.droidkaigi.confsched2022.feature.sessions
 
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.TimetableItemWithFavorite
 import io.github.droidkaigi.confsched2022.ui.UiLoadState
 
-data class SessionDetailUiModel(val state: UiLoadState<TimetableItemWithFavorite>)
+data class SessionDetailUiModel(
+    val state: UiLoadState<TimetableItemWithFavorite>,
+    val appError: AppError?
+)
diff --git a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetailViewModel.kt b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetailViewModel.kt
index 54952434b..ad7b4d9c7 100644
--- a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetailViewModel.kt
+++ b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/SessionDetailViewModel.kt
@@ -3,12 +3,15 @@ package io.github.droidkaigi.confsched2022.feature.sessions
 import androidx.compose.runtime.State
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import app.cash.molecule.AndroidUiDispatcher
 import app.cash.molecule.RecompositionClock.ContextClock
 import dagger.hilt.android.lifecycle.HiltViewModel
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.SessionsRepository
 import io.github.droidkaigi.confsched2022.model.TimetableItemId
 import io.github.droidkaigi.confsched2022.ui.UiLoadState
@@ -30,16 +33,22 @@ class SessionDetailViewModel @Inject constructor(
     private val timetableItemId: TimetableItemId =
         TimetableItemId(requireNotNull(savedStateHandle.get<String>("id")))
 
-    val uiModel: State<SessionDetailUiModel>
+    private var appError by mutableStateOf<AppError?>(null)
 
-    init {
-        val timetableItemFlow =
-            sessionsRepository.timetableItemFlow(timetableItemId).asLoadState()
+    private val timetableItemFlow =
+        sessionsRepository.timetableItemFlow(timetableItemId).asLoadState()
 
-        uiModel = moleculeScope.moleculeComposeState(clock = ContextClock) {
+    val uiModel: State<SessionDetailUiModel> =
+        moleculeScope.moleculeComposeState(clock = ContextClock) {
             val timetableItem by timetableItemFlow.collectAsState(initial = UiLoadState.Loading)
-            SessionDetailUiModel(timetableItem)
+            SessionDetailUiModel(
+                state = timetableItem,
+                appError = appError
+            )
         }
+
+    init {
+        refresh()
     }
 
     fun onFavoriteToggle(sessionId: TimetableItemId, currentIsFavorite: Boolean) {
@@ -49,4 +58,22 @@ class SessionDetailViewModel @Inject constructor(
             )
         }
     }
+
+    fun onRetryButtonClick() {
+        refresh()
+    }
+
+    private fun refresh() {
+        viewModelScope.launch {
+            try {
+                sessionsRepository.refresh()
+            } catch (e: AppError) {
+                appError = e
+            }
+        }
+    }
+
+    fun onAppErrorNotified() {
+        appError = null
+    }
 }
diff --git a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/Sessions.kt b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/Sessions.kt
index b5a165ebc..25cf2a4c8 100644
--- a/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/Sessions.kt
+++ b/feature/sessions/src/main/java/io/github/droidkaigi/confsched2022/feature/sessions/Sessions.kt
@@ -70,7 +70,7 @@ import dev.icerock.moko.resources.compose.stringResource
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiScaffold
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiTopAppBar
 import io.github.droidkaigi.confsched2022.designsystem.theme.KaigiTheme
-import io.github.droidkaigi.confsched2022.feature.announcement.AppErrorSnackbarEffect
+import io.github.droidkaigi.confsched2022.feature.common.AppErrorSnackbarEffect
 import io.github.droidkaigi.confsched2022.model.DroidKaigi2022Day
 import io.github.droidkaigi.confsched2022.model.DroidKaigiSchedule
 import io.github.droidkaigi.confsched2022.model.TimeLine
diff --git a/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/Sponsors.kt b/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/Sponsors.kt
index 6d4845966..995d2bdd2 100644
--- a/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/Sponsors.kt
+++ b/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/Sponsors.kt
@@ -20,9 +20,11 @@ import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Divider
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
@@ -35,6 +37,7 @@ import com.google.accompanist.placeholder.material.shimmer
 import dev.icerock.moko.resources.compose.stringResource
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiScaffold
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiTopAppBar
+import io.github.droidkaigi.confsched2022.feature.common.AppErrorSnackbarEffect
 import io.github.droidkaigi.confsched2022.feature.sponsors.SponsorPlan.Gold
 import io.github.droidkaigi.confsched2022.feature.sponsors.SponsorPlan.Platinum
 import io.github.droidkaigi.confsched2022.feature.sponsors.SponsorPlan.Supporter
@@ -58,6 +61,8 @@ fun SponsorsScreenRoot(
         uiModel = uiModel,
         showNavigationIcon = showNavigationIcon,
         onNavigationIconClick = onNavigationIconClick,
+        onRetryButtonClick = { viewModel.onRetryButtonClick() },
+        onAppErrorNotified = { viewModel.onAppErrorNotified() },
         onItemClick = onItemClick
     )
 }
@@ -67,10 +72,15 @@ fun Sponsors(
     uiModel: SponsorsUiModel,
     showNavigationIcon: Boolean,
     onNavigationIconClick: () -> Unit,
+    onRetryButtonClick: () -> Unit,
+    onAppErrorNotified: () -> Unit,
     modifier: Modifier = Modifier,
     onItemClick: (url: String) -> Unit = { _ -> },
 ) {
+    val snackbarHostState = remember { SnackbarHostState() }
+
     KaigiScaffold(
+        snackbarHostState = snackbarHostState,
         modifier = modifier,
         topBar = {
             KaigiTopAppBar(
@@ -84,6 +94,12 @@ fun Sponsors(
             )
         }
     ) { innerPadding ->
+        AppErrorSnackbarEffect(
+            appError = uiModel.appError,
+            snackBarHostState = snackbarHostState,
+            onAppErrorNotified = onAppErrorNotified,
+            onRetryButtonClick = onRetryButtonClick
+        )
         when (uiModel.state) {
             Loading -> FullScreenLoading(Modifier.padding(innerPadding))
             is Success ->
@@ -101,7 +117,9 @@ fun Sponsors(
                         onItemClick = onItemClick
                     )
                 }
-            is Error -> TODO()
+            is Error -> {
+                // Do nothing
+            }
         }
     }
 }
diff --git a/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/SponsorsUiModel.kt b/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/SponsorsUiModel.kt
index bc31140dd..063e517ef 100644
--- a/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/SponsorsUiModel.kt
+++ b/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/SponsorsUiModel.kt
@@ -1,8 +1,10 @@
 package io.github.droidkaigi.confsched2022.feature.sponsors
 
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.ui.UiLoadState
 import kotlinx.collections.immutable.PersistentList
 
 data class SponsorsUiModel(
-    val state: UiLoadState<PersistentList<SponsorItem>>
+    val state: UiLoadState<PersistentList<SponsorItem>>,
+    val appError: AppError?
 )
diff --git a/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/SponsorsViewModel.kt b/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/SponsorsViewModel.kt
index 7ec6b4cbb..c3f81c126 100644
--- a/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/SponsorsViewModel.kt
+++ b/feature/sponsors/src/main/java/io/github/droidkaigi/confsched2022/feature/sponsors/SponsorsViewModel.kt
@@ -3,6 +3,8 @@ package io.github.droidkaigi.confsched2022.feature.sponsors
 import androidx.compose.runtime.State
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import app.cash.molecule.AndroidUiDispatcher
@@ -13,6 +15,7 @@ import io.github.droidkaigi.confsched2022.feature.sponsors.SponsorItem.Title
 import io.github.droidkaigi.confsched2022.feature.sponsors.SponsorPlan.Gold
 import io.github.droidkaigi.confsched2022.feature.sponsors.SponsorPlan.Platinum
 import io.github.droidkaigi.confsched2022.feature.sponsors.SponsorPlan.Supporter
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.Plan
 import io.github.droidkaigi.confsched2022.model.Plan.GOLD
 import io.github.droidkaigi.confsched2022.model.Plan.PLATINUM
@@ -26,26 +29,35 @@ import kotlinx.collections.immutable.PersistentList
 import kotlinx.collections.immutable.toPersistentList
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class SponsorsViewModel @Inject constructor(
-    sponsorsRepository: SponsorsRepository
+    private val sponsorsRepository: SponsorsRepository
 ) : ViewModel() {
     private val moleculeScope =
         CoroutineScope(viewModelScope.coroutineContext + AndroidUiDispatcher.Main)
 
-    val uiModel: State<SponsorsUiModel>
+    private val sponsorsFlow = sponsorsRepository
+        .sponsors()
+        .map { it.mapToSponsorItems() }
+        .asLoadState()
 
-    init {
-        val sponsorsFlow = sponsorsRepository.sponsors()
-            .map { it.mapToSponsorItems() }
-            .asLoadState()
+    private var appError by mutableStateOf<AppError?>(null)
 
-        uiModel = moleculeScope.moleculeComposeState(clock = ContextClock) {
-            val sponsors by sponsorsFlow.collectAsState(initial = UiLoadState.Loading)
-            SponsorsUiModel(sponsors)
-        }
+    val uiModel: State<SponsorsUiModel> = moleculeScope.moleculeComposeState(
+        clock = ContextClock
+    ) {
+        val sponsorLoadState by sponsorsFlow.collectAsState(initial = UiLoadState.Loading)
+        SponsorsUiModel(
+            state = sponsorLoadState,
+            appError = appError
+        )
+    }
+
+    init {
+        refresh()
     }
 
     private fun PersistentList<Sponsor>.mapToSponsorItems(): PersistentList<SponsorItem> {
@@ -87,4 +99,22 @@ class SponsorsViewModel @Inject constructor(
             link = link
         )
     }
+
+    fun onRetryButtonClick() {
+        refresh()
+    }
+
+    private fun refresh() {
+        viewModelScope.launch {
+            try {
+                sponsorsRepository.refresh()
+            } catch (e: AppError) {
+                appError = e
+            }
+        }
+    }
+
+    fun onAppErrorNotified() {
+        appError = null
+    }
 }
diff --git a/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/Staff.kt b/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/Staff.kt
index 3590e8bfd..02473ecc7 100644
--- a/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/Staff.kt
+++ b/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/Staff.kt
@@ -7,9 +7,11 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.Preview
@@ -19,6 +21,7 @@ import io.github.droidkaigi.confsched2022.designsystem.components.KaigiScaffold
 import io.github.droidkaigi.confsched2022.designsystem.components.KaigiTopAppBar
 import io.github.droidkaigi.confsched2022.designsystem.components.UsernameRow
 import io.github.droidkaigi.confsched2022.designsystem.theme.KaigiTheme
+import io.github.droidkaigi.confsched2022.feature.common.AppErrorSnackbarEffect
 import io.github.droidkaigi.confsched2022.model.Staff
 import io.github.droidkaigi.confsched2022.model.fakes
 import io.github.droidkaigi.confsched2022.strings.Strings
@@ -35,7 +38,15 @@ fun StaffScreenRoot(
     onLinkClick: (url: String, packageName: String?) -> Unit = { _, _ -> }
 ) {
     val uiModel by viewModel.uiModel
-    Staff(uiModel, showNavigationIcon, onNavigationIconClick, onLinkClick, modifier)
+    Staff(
+        uiModel = uiModel,
+        showNavigationIcon = showNavigationIcon,
+        onNavigationIconClick = onNavigationIconClick,
+        onRetryButtonClick = { viewModel.onRetryButtonClick() },
+        onAppErrorNotified = { viewModel.onAppErrorNotified() },
+        onLinkClick = onLinkClick,
+        modifier = modifier
+    )
 }
 
 @Composable
@@ -43,10 +54,15 @@ fun Staff(
     uiModel: StaffUiModel,
     showNavigationIcon: Boolean,
     onNavigationIconClick: () -> Unit,
+    onRetryButtonClick: () -> Unit,
+    onAppErrorNotified: () -> Unit,
     onLinkClick: (url: String, packageName: String?) -> Unit,
     modifier: Modifier = Modifier
 ) {
+    val snackbarHostState = remember { SnackbarHostState() }
+
     KaigiScaffold(
+        snackbarHostState = snackbarHostState,
         topBar = {
             KaigiTopAppBar(
                 showNavigationIcon = showNavigationIcon,
@@ -59,9 +75,17 @@ fun Staff(
             )
         }
     ) { innerPadding ->
+        AppErrorSnackbarEffect(
+            appError = uiModel.appError,
+            snackBarHostState = snackbarHostState,
+            onAppErrorNotified = onAppErrorNotified,
+            onRetryButtonClick = onRetryButtonClick
+        )
         Box(modifier = Modifier.padding(innerPadding)) {
             when (uiModel.state) {
-                is Error -> TODO()
+                is Error -> {
+                    // Do nothing
+                }
                 is Loading -> Box(
                     modifier = Modifier.fillMaxSize(),
                     contentAlignment = Alignment.Center,
@@ -97,10 +121,13 @@ fun StaffPreview() {
             uiModel = StaffUiModel(
                 state = Success(
                     Staff.fakes()
-                )
+                ),
+                appError = null,
             ),
             showNavigationIcon = true,
             onNavigationIconClick = {},
+            onRetryButtonClick = {},
+            onAppErrorNotified = {},
             onLinkClick = { _, _ -> },
         )
     }
diff --git a/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/StaffUiModel.kt b/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/StaffUiModel.kt
index 9fb9d4e41..b8c0836fe 100644
--- a/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/StaffUiModel.kt
+++ b/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/StaffUiModel.kt
@@ -1,7 +1,11 @@
 package io.github.droidkaigi.confsched2022.feature.staff
 
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.Staff
 import io.github.droidkaigi.confsched2022.ui.UiLoadState
 import kotlinx.collections.immutable.PersistentList
 
-data class StaffUiModel(val state: UiLoadState<PersistentList<Staff>>)
+data class StaffUiModel(
+    val state: UiLoadState<PersistentList<Staff>>,
+    val appError: AppError?,
+)
diff --git a/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/StaffViewModel.kt b/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/StaffViewModel.kt
index 3f1e5e179..7cc69321c 100644
--- a/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/StaffViewModel.kt
+++ b/feature/staff/src/main/java/io/github/droidkaigi/confsched2022/feature/staff/StaffViewModel.kt
@@ -3,33 +3,62 @@ package io.github.droidkaigi.confsched2022.feature.staff
 import androidx.compose.runtime.State
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import app.cash.molecule.AndroidUiDispatcher
 import app.cash.molecule.RecompositionClock.ContextClock
 import dagger.hilt.android.lifecycle.HiltViewModel
+import io.github.droidkaigi.confsched2022.model.AppError
 import io.github.droidkaigi.confsched2022.model.StaffRepository
 import io.github.droidkaigi.confsched2022.ui.UiLoadState.Loading
 import io.github.droidkaigi.confsched2022.ui.asLoadState
 import io.github.droidkaigi.confsched2022.ui.moleculeComposeState
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class StaffViewModel @Inject constructor(
-    staffRepository: StaffRepository,
+    private val staffRepository: StaffRepository,
 ) : ViewModel() {
     private val moleculeScope =
         CoroutineScope(viewModelScope.coroutineContext + AndroidUiDispatcher.Main)
 
-    val uiModel: State<StaffUiModel>
+    private val staffFlow = staffRepository
+        .staff()
+        .asLoadState()
+
+    private var appError by mutableStateOf<AppError?>(null)
+
+    val uiModel: State<StaffUiModel> = moleculeScope.moleculeComposeState(clock = ContextClock) {
+        val staffState by staffFlow.collectAsState(initial = Loading)
+        StaffUiModel(
+            state = staffState,
+            appError = appError,
+        )
+    }
 
     init {
-        val dataFlow = staffRepository.staff().asLoadState()
+        refresh()
+    }
 
-        uiModel = moleculeScope.moleculeComposeState(clock = ContextClock) {
-            val data by dataFlow.collectAsState(initial = Loading)
-            StaffUiModel(data)
+    fun onRetryButtonClick() {
+        refresh()
+    }
+
+    private fun refresh() {
+        viewModelScope.launch {
+            try {
+                staffRepository.refresh()
+            } catch (e: AppError) {
+                appError = e
+            }
         }
     }
+
+    fun onAppErrorNotified() {
+        appError = null
+    }
 }