I keep my old XP workstation going for simple tasks like email and data storage and I tried to send an email several times to 1 domain/1 email address and it continually bounced back with this:
An unknown error has occurred. Subject 'some subject line with no links in it', Account: 'GoDaddy mail account', Server: 'smtpout.secureserver.net', Protocol: SMTP, Server Response: '554 Message refused.', Port: 80, Secure(SSL): No, Server Error: 554, Error Number: 0x800CCC6F
The email message has zero hyperlinks (a href anchors) or references to other web sites in it. There was a PDF attachment I created using CutePDF Writer, but other than that the message was just a plain email in RTF format. I never did try sending it via "text" format though, and I suspect that might've worked, but I'm also hinging on the PDF, that maybe the receiving domain's mail server didn't like and I say that because I have no problems sending to anyone else on any different domain with the same attachment.
When I go into the WEBMAIL version of my POP/SMTP account, it sends the email "as is" with the attachment just fine. FYI - I tried changing the outgoing ports for SMTP to 25, 110 and 3535 as is consistent with GoDaddy's email FAQ instructions. None of the ports made a difference and outgoing authentication was "checked/enabled" in all attempts to send via Outlook Express.
So do ya'll think its firewall rules on the receiver's mail server? That is my bet right now as I wasn't running antivirus when I tried to send the message.