I can't send any outgoing mail and get this error

The message could not be sent. The setting for your outgoing email [SMTP] server might need to be configured. To find the server settings for '*** Email address is removed for privacy ***', please contact your email service provider.

Subject 'Exc'
Server Error: 550
Server Response: 550 5.1.1 Not our Customer
Server: 'smtp.comcast.net'
Windows Live Mail Error ID: 0x800CCC79
Protocol: SMTP
Port: 465
Secure(SSL): Yes