Hi ! For whatever reason logging of wrong Dovecot stopped working (possibly after upgrade of ISPConfig to 3.13 or Debian 9 security patches), but unfortunately I can't say for sure. tail -n 1000000 /var/log/mail.log | grep pop3-login | grep failed shows failed entries, however tail -n 1000000 /var/log/mail.log | grep mismatch shows nothing - no recorded bogus passwords. Options in /etc/dovecot/conf.d/10-logging.conf auth_verbose = yes auth_verbose_passwords = plain auth_debug_passwords = yes What is a cause of such problem? Thanks in advance for any suggestion(s).