How to find out why pop3 and pop3s don't work, dovecot?

Question

Debian

Hello, I ran into a problem. Authorization by pop3 does not work if everything is fine with imap or imaps. Tell me how to log connections and how can I even determine what the problem might be? I will accept any help, links, suggestions.
There is a suspicion that this line in the log has nothing to do with my problem, but I threw it off just in case.

/var/log/mail.log

May  6 15:10:01 web dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=127.0.0.1, lip=127.0.0.1, secured, session=<9DDFbohrqsd/AAAB>

I execute commands

netstat -tnp | grep 110
netstat -tnp | grep 995

And in response, silence, the problem is that no one listens to the pop3 ports, that's just why the dovecot does not listen to them. While I understand.
Thank you all for your time.