diff --git a/backend/ai_server.py b/backend/ai_server.py
index 7351092..d516e05 100644
--- a/backend/ai_server.py
+++ b/backend/ai_server.py
@@ -383,6 +383,13 @@ def predict_batch(req: PredictBatchRequest):
             "error": _MODEL_ERROR or f"YOLO model not found: {DEFAULT_MODEL_PATH}",
         }
 
+    if DETECTION_LABELS_PATH is None or _LABEL_ERROR:
+        return {
+            "ok": False,
+            "predictions": [],
+            "error": f"detection labels missing: {_LABEL_ERROR}",
+        }
+
     imgsz = int(req.imageSize or _IMGSZ or 640)
 
     try:
diff --git a/backend/server.go b/backend/server.go
index a402c0b..be1533a 100644
--- a/backend/server.go
+++ b/backend/server.go
@@ -314,7 +314,7 @@ func startAIServer(ctx context.Context) (*aiServerProcess, error) {
 	args = append(args,
 		"-m", "uvicorn",
 		"ai_server:app",
-		"--host", "127.0.0.1",
+		"--host", "0.0.0.0",
 		"--port", port,
 		"--log-level", "error",
 	)