diff --git a/backend/src/services/scheduledMessages.service.ts b/backend/src/services/scheduledMessages.service.ts
index 074a7f3..3ef31a0 100644
--- a/backend/src/services/scheduledMessages.service.ts
+++ b/backend/src/services/scheduledMessages.service.ts
@@ -37,6 +37,7 @@ interface RoomInfo {
 interface RoomsResult {
   configured: boolean;
   data?: RoomInfo[];
+  error?: string;
 }
 
 // ── Helpers ──────────────────────────────────────────────────────────────────
@@ -327,7 +328,7 @@ async function getRooms(): Promise<RoomsResult> {
     logger.error('scheduledMessages.getRooms failed', {
       error: error instanceof Error ? error.message : String(error),
     });
-    return { configured: false };
+    return { configured: true, data: [], error: 'Verbindung zu Nextcloud fehlgeschlagen' };
   }
 }
 
diff --git a/frontend/src/pages/GeplanteMachrichtenForm.tsx b/frontend/src/pages/GeplanteMachrichtenForm.tsx
index 5cf8502..0ce2d95 100644
--- a/frontend/src/pages/GeplanteMachrichtenForm.tsx
+++ b/frontend/src/pages/GeplanteMachrichtenForm.tsx
@@ -167,6 +167,7 @@ export default function GeplanteMachrichtenForm({ ruleId }: GeplanteMachrichtenF
   const isEventType = messageType === 'fahrzeug_event';
   const rooms = roomsData?.data ?? [];
   const roomsConfigured = roomsData?.configured ?? false;
+  const roomsError = roomsData?.error;
 
   if (ruleId && ruleLoading) {
     return (
@@ -308,6 +309,10 @@ export default function GeplanteMachrichtenForm({ ruleId }: GeplanteMachrichtenF
                 <Alert severity="warning" sx={{ mt: 1 }}>
                   Bot-Konto nicht konfiguriert. Bitte in den Admin-Einstellungen unter Nextcloud konfigurieren.
                 </Alert>
+              ) : roomsError ? (
+                <Alert severity="error" sx={{ mt: 1 }}>
+                  Nextcloud nicht erreichbar — Raumliste kann nicht geladen werden.
+                </Alert>
               ) : (
                 <Select
                   value={targetRoomToken}
diff --git a/frontend/src/types/scheduledMessages.types.ts b/frontend/src/types/scheduledMessages.types.ts
index 012a816..2db2a89 100644
--- a/frontend/src/types/scheduledMessages.types.ts
+++ b/frontend/src/types/scheduledMessages.types.ts
@@ -49,4 +49,5 @@ export interface ScheduledMessageDetailResponse {
 export interface RoomsResponse {
   configured: boolean;
   data?: NextcloudRoom[];
+  error?: string;
 }