Originally Posted by plumsauce
Anyways, since you can't get out on 25, try sending from one on box account to another on box account and see what happens.
Thanks for the replies. How would I try this?
Anyway, strangely enough, any attempt to telnet email through the relay server is refused. Maybe I did something wrong. I've provided the telnet session below. And again, just to be clear, any of my users can send any email except when it contains  on its own line. And yes, godaddy has acknowledged this.
220 k2smtpout03-01.prod.mesa1.secureserver.net ESMTP
250 Sender accepted.
250 Recipient accepted.
354 End your message with a period.
554 Message refused.