- automatic restart (restart it and figure out the cause later),
- installing a documentation command in the service configuration to figure out what is wrong through "systemctl status servicename", and
- a one liner to show connections for a service:
ps -e -o pid,cgroup \ | awk '$2 ~ /dovecot.service/ {print "-p", $1}' \ | xargs -r lsof -n -i -a