I've followed the guides to installing Exim, Dovecote and I have Bind installed as well.
SquirrelMail appears to be working. However, in Thunderbird, when I try to send a test email:
"Sending of the message failed.
The message could not be sent because connecting to Outgoing server (SMTP) mail.domain.com failed. The server may be unavailable or is refusing SMTP connections. Please verify that your Outgoing server (SMTP) settings are correct and try again."
This is my first time setting up my own mail server and I'm not entirely sure what I'm doing but I definitely want to learn how to set it up and how to troubleshoot this with Webuzo.