diff --git a/snowflake-api/examples/tracing/src/main.rs b/snowflake-api/examples/tracing/src/main.rs
index 2c1c002..dd8e834 100644
--- a/snowflake-api/examples/tracing/src/main.rs
+++ b/snowflake-api/examples/tracing/src/main.rs
@@ -57,7 +57,7 @@ async fn run_in_span(api: &snowflake_api::SnowflakeApi) -> anyhow::Result<()> {
 
     match res {
         QueryResult::Arrow(a) => {
-            println!("{}", pretty_format_batches(&a).unwrap());
+            println!("{}", pretty_format_batches(&a[..]).unwrap());
         }
         QueryResult::Json(j) => {
             println!("{}", j);
diff --git a/snowflake-api/src/responses.rs b/snowflake-api/src/responses.rs
index 9a687fa..52eaeae 100644
--- a/snowflake-api/src/responses.rs
+++ b/snowflake-api/src/responses.rs
@@ -11,7 +11,6 @@ pub enum ExecResponse {
     Error(ExecErrorResponse),
 }
 
-// todo: add close session response, which should be just empty?
 #[allow(clippy::large_enum_variant)]
 #[derive(Deserialize, Debug)]
 #[serde(untagged)]
@@ -21,6 +20,8 @@ pub enum AuthResponse {
     Renew(RenewSessionResponse),
     Close(CloseSessionResponse),
     Error(AuthErrorResponse),
+    ExecError(ExecErrorResponse),
+    Other(serde_json::Value),
 }
 
 #[derive(Deserialize, Debug)]
@@ -53,9 +54,8 @@ pub struct ExecErrorResponseData {
     pub line: Option<i64>,
     pub pos: Option<i64>,
 
-    // fixme: only valid for exec query response error? present in any exec query response?
-    pub query_id: String,
-    pub sql_state: String,
+    pub query_id: Option<String>,
+    pub sql_state: Option<String>,
 }
 
 #[derive(Deserialize, Debug)]
diff --git a/snowflake-api/src/session.rs b/snowflake-api/src/session.rs
index 90acaaf..48a6960 100644
--- a/snowflake-api/src/session.rs
+++ b/snowflake-api/src/session.rs
@@ -35,7 +35,7 @@ pub enum AuthError {
     MissingCertificate,
 
     #[error("Unexpected API response")]
-    UnexpectedResponse,
+    UnexpectedResponse(Option<serde_json::Value>),
 
     // todo: add code mapping to meaningful message and/or refer to docs
     //   eg https://docs.snowflake.com/en/user-guide/key-pair-auth-troubleshooting
@@ -269,7 +269,12 @@ impl Session {
                     e.code.unwrap_or_default(),
                     e.message.unwrap_or_default(),
                 )),
-                _ => Err(AuthError::UnexpectedResponse),
+                AuthResponse::ExecError(e) => Err(AuthError::AuthFailed(
+                    e.code.unwrap_or_default(),
+                    e.message.unwrap_or_default(),
+                )),
+                AuthResponse::Other(value) => Err(AuthError::UnexpectedResponse(Some(value))),
+                _ => Err(AuthError::UnexpectedResponse(None)),
             }
         } else {
             Ok(())
@@ -356,7 +361,12 @@ impl Session {
                 e.code.unwrap_or_default(),
                 e.message.unwrap_or_default(),
             )),
-            _ => Err(AuthError::UnexpectedResponse),
+            AuthResponse::ExecError(e) => Err(AuthError::AuthFailed(
+                e.code.unwrap_or_default(),
+                e.message.unwrap_or_default(),
+            )),
+            AuthResponse::Other(value) => Err(AuthError::UnexpectedResponse(Some(value))),
+            _ => Err(AuthError::UnexpectedResponse(None)),
         }
     }
 
@@ -416,7 +426,12 @@ impl Session {
                 e.code.unwrap_or_default(),
                 e.message.unwrap_or_default(),
             )),
-            _ => Err(AuthError::UnexpectedResponse),
+            AuthResponse::ExecError(e) => Err(AuthError::AuthFailed(
+                e.code.unwrap_or_default(),
+                e.message.unwrap_or_default(),
+            )),
+            AuthResponse::Other(value) => Err(AuthError::UnexpectedResponse(Some(value))),
+            _ => Err(AuthError::UnexpectedResponse(None)),
         }
     }
 }