Oddest thing... I have one site on the server. I am using Firefox Thunderbird to collect mail. It recognizes the imap server, and the password too, but still won't send mail. This is what I have: mail.example.com pointing to public IP in ISPConfig 3 (A record). I did an IP lookup of mail.example.com and my IP was correctly resolved. In the "Monitor", the only error I am receiving is DNS "offline" How can this be? The site loads fine. How could there be DNS errors yet the only site loads? No error logs in mail. How does the IP resolve, Thunderbird recognizes the address and password, but no mail can be sent?