diff --git a/lib/Listener/AppDisableListener.php b/lib/Listener/AppDisableListener.php
index 1dc2c132..66f16c63 100644
--- a/lib/Listener/AppDisableListener.php
+++ b/lib/Listener/AppDisableListener.php
@@ -48,7 +48,9 @@ public function handle(Event $event): void {
 			}
 
 			$this->providerConfig->removeProvider($appId, $providerId);
-			$this->actionService->deleteProvider($providerId);
+			// deleteProvider() expects the full provider key (appId__providerId),
+			// not the bare provider id; $key already holds that full key.
+			$this->actionService->deleteProvider($key);
 		}
 	}
 }
diff --git a/lib/Service/ActionScheduler.php b/lib/Service/ActionScheduler.php
index 0e93327c..5a38fd96 100644
--- a/lib/Service/ActionScheduler.php
+++ b/lib/Service/ActionScheduler.php
@@ -64,7 +64,10 @@ public function deleteSources(array $sourceIds): void {
 	}
 
 	/**
-	 * @param string $providerKey
+	 * @param string $providerKey The full provider key in the form appId__providerId
+	 *                            (e.g. "mail__mail"), as returned by
+	 *                            ProviderConfigService::getConfigKey(). Passing a bare
+	 *                            provider id makes the backend reject the whole action batch.
 	 * @return void
 	 * @throws Exception
 	 */