Hello,
My sysadmin and I spent a couple hours trying to figure out a POP3 problem that has worked for about 20 or so years.
We run our own dns for sgeinc.com. I've always used mail.sgeinc.com as my incoming and outgoing server. At various times mail has been an alias for another machine. It's currently on the same address as sge.sgeinc.com. On the update forced on us on 2/22/24 or 2/23/24 it stopped working. It still works as an outgoing server but incoming POP3 it stopped working. It started working when I changed my incoming server to sge.sgeinc.com. You might want to look into it or not. We chased the initial problem to, we think, ssh-keygen in /usr/local/bin/ which was Not found but is there.
Thanks
root@sge:/usr/local/bin# dovecot -n # 2.3.7.2 (3c910f64b): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.7.2 () # OS: Linux 5.4.0-172-generic x86_64 Ubuntu 20.04.6 LTS # Hostname: sge.sgeinc.com auth_mechanisms = plain login mail_location = maildir:~/Maildir namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { driver = pam } protocols = " imap lmtp pop3" service auth { unix_listener /var/spool/postfix/private/auth { mode = 0666 } unix_listener auth-userdb { group = postfix mode = 0660 user = postfix } } service pop3-login { inet_listener pop3 { port = 110 } } ssl = required ssl_cert = </etc/letsencrypt/live/sgeinc.com/fullchain.pem ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it userdb { driver = passwd }