Chatbot by facebook messenger

Dear Team,

I made a chatbot. It is working well on my side but tester of Facebook Messenger team say that there is no responding from AppSheet Chatbot.
Which plan i need to use to have workable chatbot? Shall i use publish plan or?
Thanks in advance.

As chatbot apps don’t require user authentication, it should be on Publisher Pro plan.

Dear Levent,
Still not working even plan is publish pro. Here is what i got from Facebbok.

Your Webhooks subscription for callback URL has not been accepting updates for at least 10 minutes. Please verify that your callback server is functioning. Visit our reference documentation to learn how to update your callback URL.