Chat bot callback url not working

[Problem/Question]
We created a chat bot with callback url using ngrok which points to our local environment for debugging. However we didn’t see anything coming after we sent a bot message. How can we debug it? Our App ID is C86F9327-18B9-441A-A601-88B6A5C527F8

Thank you!
Min

Hello @Min_Ju,

As the bot is set up successfully at your end, can you please confirm if you are testing this behaviour on the old channels or newly created channels. If this is for an old channel based on your preference setting you need to join the bot manually into the group channel following this API endpoint.

However, if the issue is related to the new channels that are created after the bot creation, kindly share the channel_url and I’ll further look into it.

Thank you so much @Thanraj! It should be in the old channel so I will follow your instruction and retry with it. Much appreciated!

Min