I've installed Roundcube and setup email in ISPConfig. Everything works fine if I try to send to and from Roundcube, but when I try to configure Microsoft Mail, Outlook, Thunderbird, etc. I can't get the system to send mail, it only receives. I assume since it works in Roundcube fine the installation is configured properly, I just don't know the server address and/or proper port number to configure mail apps. Can anyone recommend how to find the address and port number so I can verify the mail apps are configured properly?
Use the server hostname as mail server. The imap and pop3 ports are standard, for sending use port 587.
