Split from this thread.
I too am having problems with emails not sending from my Windows Live Mail account. The error message I am getting is :
The message could not be sent because the server rejected the sender's email address.
Server Error: 530
Server Response: 530 Authentication Required (VM401)
Windows Live Mail Error ID: 0x800CCC78
Not sure what I need to do to make my outgoing server require authentication.
Hope you can help.