I am still getting issues described here:
Sorry for not answering there, but it worked once so I didn't need to fix it.
The problem is in sessions.
I added max_retries there but it didn't work.
I changed this line: certbot/client.py at master · certbot/certbot · GitHub
response = requests.request(method, url, *args, **kwargs)
and it works well now for me.
Is there a regular way how to fix it without forking certbot and change that line and then install it from source?