diff --git a/rag/app/tag.py b/rag/app/tag.py
index 179d72e24..de2ce0fa6 100644
--- a/rag/app/tag.py
+++ b/rag/app/tag.py
@@ -138,6 +138,8 @@ def label_question(question, kbs):
         else:
             all_tags = json.loads(all_tags)
         tag_kbs = KnowledgebaseService.get_by_ids(tag_kb_ids)
+        if not tag_kbs:
+            return tags
         tags = settings.retrievaler.tag_query(question,
                                               list(set([kb.tenant_id for kb in tag_kbs])),
                                               tag_kb_ids,