Dash App Runs Perfectly in the local environment but not on Heroku

Dear all, my code runs perfectly in my local ubuntu environment but keeps receiving timeout errors on Heroku. The weird thing is, after inspecting the app using Chrome, I could not find any process exceeding a response time of 30 s.

I suspect that the Heroku environment wrongly activated my callback functions which already have the setting ‘prevent_initial_call=True’.

This is my code:

Part of the Heroku log:

2020-12-21T18:51:30.619003+00:00 app[web.1]: [2020-12-21 18:51:30 +0000] [9] [INFO] Booting worker with pid: 9
2020-12-21T18:51:30.728185+00:00 app[web.1]: [2020-12-21 18:51:30 +0000] [17] [INFO] Booting worker with pid: 17
2020-12-21T18:51:31.138877+00:00 heroku[web.1]: State changed from starting to up
2020-12-21T18:51:47.739769+00:00 heroku[web.1]: Error R12 (Exit timeout) → At least one process failed to exit within 30 seconds of SIGTERM
2020-12-21T18:51:47.742997+00:00 heroku[web.1]: Stopping remaining processes with SIGKILL
2020-12-21T18:51:47.907220+00:00 heroku[web.1]: Process exited with status 137

Thank you very much.

push upward~~~~~~~~~~~~~~~~~~