I don't really know if this is a problem or not, but I have not been able to enable SSL and also use a username/password for authentication. I believe this has to do with the order in which System.Net.Mail sends the commands to the SMTP server. For whatever reason I received an "Authentication failed" exception from the remote SMTP server. As soon as I turned SSL off, everything worked. If I didn't set a username/password, the SSL session worked just fine. It was the combination of SSL and a username/password that wouldn't let me email.