Before you used Gmail to retrieve your email from a Virtualmin server. It suddenly stops working and you see this error in Gmail:
SSL Security Error. [ Help ]
Server returned error “SSL error: No path found from the leaf certificate to any root. Maybe an int…”
Digging further you see this:
Gmail: Error fetching mail. Mail from this account has not been retrieved since Sep 1. View details
When you SSH to the server and observe the log file you see this:
Nov 23 10:58:53 vps4900-gxm dovecot: pop3-login: Disconnected (no auth attempts in 1 secs): user=<>, rip=220.127.116.11, lip=xxx.yyy.250.85, TLS: Connection closed, session=<C0hPMVF7npDRVdCi>
The 18.104.22.168 is Google’s IP, and the second IP is your IP.
Basically something went wrong with your SSL certificate. Possibly you used Let’s Encrypt and it’s expired, or your configuration went wrong.
The workaround is to use port 110 instead of 995, and turn off SSL.