Split from this thread.

I am having the identical issue and ended up FRUSTRATED!!!

Here's the message:

The message could not be sent because the server rejected the sender's email address. The sender's email address was '*** Email address is removed for privacy ***'.

Subject 'Happy Thanks giving'
Server Error: 550
Server Response: 550 5.7.1 relaying denied
Server: 'mail.bresnan.net'
Windows Live Mail Error ID: 0x800CCC78
Protocol: SMTP
Port: 25
Secure(SSL): No