So I have set up a mailserver today following this guide.
The only problem with the guide itself was that dovecot.conf was in /usr/share/dovecot and not in the location specified in the guide.
When I had installed squirrelmail and tried to login with my test mail account called mailtester, it first gave me an error like ERROR: Connection dropped by IMAP server. By reading the logs I figured out it couldn't find the mail directory, so I created it under /home/mailtester/mail and I could login.
Now the problem is whenever I try to send a mail from within squirrel I get:
Message not sent. Server replied: Service not available, closing channel 421 4.3.0 collect: Cannot write ./dfr04CRfQT012544 (bfcommit, uid=0, gid=114): No such file or directory
Also when I send an email to email@example.com (where mydomain.com is my domain) I don't seem to receive it.
I also checked this which gave me:
(I blacked out my server's IP and domain)
Any ideas how to fix this?