if thread_id is None or thread_id == "":

app.py

@@ -1007,7 +1007,7 @@ def chat_with_youtube_transcript(youtube_id, thread_id, user_message, chat_histo
     assistant_id = "asst_kmvZLNkDUYaNkMNtZEAYxyPq"
     client = OPEN_AI_CLIENT
     # 创建线程
-    if thread_id is None:
+    if thread_id is None or thread_id == "":
         thread = client.beta.threads.create()
         # 向线程添加初始系统消息，指定使用的 YouTube 视频ID
         client.beta.threads.messages.create(