diff --git a/lib/bot.php b/lib/bot.php
index 240e149..911e85f 100644
--- a/lib/bot.php
+++ b/lib/bot.php
@@ -288,16 +288,6 @@ function doarchive(
             $pdata .= str_repeat('=', $level) . $array['header'] . str_repeat('=', $level) . $array['content'];
         }
 
-        if (substr(strtolower(str_replace('_', ' ', $archiveprefix)), 0, strlen($page)) != strtolower($page)) {
-            $expected_key = hash('sha256', trim($page) . trim($config->archiveprefix) . trim(Config::$archive_key));
-            if (trim($key) != $expected_key) {
-                $logger->error(
-                    'Incorrect key for archive prefix; page=' . $page . ', prefix=' . $config->archiveprefix
-                );
-                $archiveprefix = $page . '/Archives/';
-            }
-        }
-
         if ($age == '99999') {
             $age = 0;
         }
diff --git a/lib/config/functions.php b/lib/config/functions.php
index 9351ed7..48eff05 100644
--- a/lib/config/functions.php
+++ b/lib/config/functions.php
@@ -304,6 +304,17 @@ function build_config_from_config_block(string $page, RawConfig $block)
         $config->once = $options['once'] === '1';
     }
 
+    // If the archive prefix is not under the same page, then it requires a key,
+    // verify the key is correct, otherwise use a default archive prefix.
+    if (substr(strtolower(str_replace('_', ' ', $config->archiveprefix)), 0, strlen($page)) != strtolower($page)) {
+        $expected_key = hash('sha256', trim($page) . trim($config->archiveprefix) . trim(Config::$archive_key));
+        if ($config->key != $expected_key) {
+            $logger->error('Incorrect key for archive prefix; page=' . $page . ', prefix=' . $config->archiveprefix);
+            $config->archiveprefix = $page . '/Archives/';
+            $config->key = DefaultConfig::$key;
+        }
+    }
+
     $config->is_valid = true;
     return $config;
 }
diff --git a/tests/ConfigGenerationTest.php b/tests/ConfigGenerationTest.php
index 4af8bc3..582302f 100644
--- a/tests/ConfigGenerationTest.php
+++ b/tests/ConfigGenerationTest.php
@@ -68,4 +68,20 @@ public function testGeneratedConfigMatchesExpectedConfig(
 
         $this->assertEquals($generated_config, $expected_config);
     }
+
+    public function testMismatchedArchivePrefixWithoutValidKeyResetsToDefault(): void
+    {
+        $raw_config = '{{User:ClueBot III/ArchiveThis' .
+            '|archiveprefix=Some Other Page/Archives/' .
+            '|key=totally-wrong-key' .
+            '|format=Y/F}}';
+
+        $config_blocks = find_config_blocks("ClueBot III", $raw_config);
+        $this->assertCount(1, $config_blocks);
+
+        $config = build_config_from_config_block("Test Page", $config_blocks[0]);
+
+        $this->assertEquals("Test Page/Archives/", $config->archiveprefix);
+        $this->assertEquals(DefaultConfig::$key, $config->key);
+    }
 }
diff --git a/tests/data/config-snippets/invalid-key/meta.json b/tests/data/config-snippets/invalid-key/meta.json
new file mode 100644
index 0000000..b35f26e
--- /dev/null
+++ b/tests/data/config-snippets/invalid-key/meta.json
@@ -0,0 +1,3 @@
+{
+    "title": "Talk:Example Page"
+}
diff --git a/tests/data/config-snippets/invalid-key/normative.txt b/tests/data/config-snippets/invalid-key/normative.txt
new file mode 100644
index 0000000..1a30efd
--- /dev/null
+++ b/tests/data/config-snippets/invalid-key/normative.txt
@@ -0,0 +1,4 @@
+{{User:ClueBot III/ArchiveThis
+|archiveprefix=Talk:Example Page/Archives/
+|age=2160
+}}
\ No newline at end of file
diff --git a/tests/data/config-snippets/invalid-key/page.txt b/tests/data/config-snippets/invalid-key/page.txt
new file mode 100644
index 0000000..6d06bd8
--- /dev/null
+++ b/tests/data/config-snippets/invalid-key/page.txt
@@ -0,0 +1 @@
+{{User:ClueBot III/ArchiveThis|archiveprefix=Talk:NotMyPage/Archive|age=2160|key=invalid}}