Dovecot cannot start at boot. Mail log shows this error after boot: Code: # tail -f /var/log/mail.log Jun 19 10:09:53 host postfix/smtpd: warning: SASL: Connect to private/auth failed: Connection refused Jun 19 10:09:53 host postfix/smtpd: fatal: no SASL authentication mechanisms Jun 19 10:09:54 host postfix/master: warning: process /usr/lib/postfix/smtpd pid 3126 exit status 1 Jun 19 10:09:54 host postfix/master: warning: /usr/lib/postfix/smtpd: bad command startup -- throttling emails cannot be delivered, and I'm forced to restart Dovecot manually: #service dovecot restart , and then it works. Just I have tried a dovecot update preserving my configuration. Maybe some unexpected change? I'm with Debian Jessie Some idea why it happens?.