one config file is
/usr/share/dovecot/dovecot.conf
2023-01-27: disable pop3 by commenting it out in /usr/share/dovecot/protocols.d/pop3d.protocol
... and restarting with systemctl restart
The configuration is in
/etc/dovecot/conf.d/10-ssl.conf
The cert is created / refreshed with:
certbot certonly --webroot -w/local/bonmot/ -d mercury.bonmot.ca systemctl restart dovecot
The keys are in cert & chain /etc/letsencrypt/live/mercury.bonmot.ca/fullchain.pem key file: /etc/letsencrypt/live/mercury.bonmot.ca/privkey.pem