Hi I set up ISPConfig 3.1 system in a multi server environment (ISPConfig Panel, Web, email, db, ns). The problem I am facing at the moment is, that i am able to receive mails on a test domain but I am not able to send mails. All servers are running Ubuntu 16.04 and ISPConfig 3.1b. I Installed roundcube on the Webserver. I can login to roundcube with a given testaccount and read the mails received on the mailserver without a problem. When trying to send a mail I get the following error from roundcube: Code: SMTP Error (454): Failed to add recipient "[email protected][email protected] /var/log/mail.log on the mailserver shows the following: Code: Jul 3 16:54:33 mailserver postfix/smtpd: connect from FQDN_of_Webserver[IP_address_of_web_server] Jul 3 16:54:33 mailserver postfix/smtpd: NOQUEUE: filter: RCPT from FQDN_of_Webserver[IP_address_of_web_server]: <[email protected][email protected][email protected][email protected][email protected][email protected][email protected][email protected][email protected] I made all ips and URLs anonymous. If i look at the output of postconf -n I see that there is no hint for the domain name of the test domain in mydestinations. I think that this is the problem, but I have no glue how to add it. Any hints? Edit: I just looked into the local mariaDb table on the mailserver. It seems that there is no row in the table domain. If i correctly understood the contents of /etc/postfix/mysql-virtual_domains.cf there should be an entry for the testdomain.