Why does Timeout was reached occur in callback api in VK?

Question

Python

Good afternoon.
There is a bot for VK, to which about 200-400 people write per minute.
When a new message arrives, it adds it as a task to celery and immediately responds with 200 ok.
thus, the response to the callback is almost instantaneous.
But, very often in errors we get timeout was reached.

I don't know how to deal with it, how to deal with it, and how to track down why this is happening. In theory, this should not be, because when a new message is received, the bot throws it into the queue for processing.
another problem is when there are too many such errors, then VKontakte stops sending notifications and the bot is idle
as a framework using flask, everything works in a docker container and a redis broker