Could you please extract related log in Postfix log file in /var/log/mail.log and paste here? It's hard for us to help troubleshoot without related log.
Do you have LAMP installed before iRedMail installation?
Could you please extract related log in Postfix log file in /var/log/mail.log and paste here? It's hard for us to help troubleshoot without related log.
Do you have LAMP installed before iRedMail installation?