the parameter smtpd_enforce_tls was deprecated see: https://www.postfix.org/DEPRECATION_README.html your service might be producing a warning if you check it with `journalctl -feu postfix` "postfix[PID]: /usr/sbin/postconf: warning: /etc/postfix/master.cf: support for parameter "smtpd_enforce_tls" will be deprecated" delete the line manually like done in this commitpull/352/head