I have a new computer. Technician attempted to utilize Windows Live Mail. For over a week now I have had difficulty receiving and sending mail. He has tried to change settings - delete anit-virus program - multiple solutions with no success. The message below is what seems to be the error. Please Help!

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 'Test'
Server Error: 530
Server Response: 530 authentication required - for help go to http://help.yahoo.com/sbc/dsl/mail/pop/pop-11.html
Server: 'outbound.att.net'
Windows Live Mail Error ID: 0x800CCC78
Protocol: SMTP
Port: 465
Secure(SSL): Yes