Outlook Express not sending mail

For some reason my brother can't send mail from his
computer. He can receive it, but when trying to send he
gets the following message:

The message could not be sent because one of the
recipients was rejected by the server. The rejected e-
mail address was '.
Subject 'testing', Account: 'pop.earthlink.net',
Server: 'smtpauth.earthlink.net', Protocol: SMTP, Server
Response: '550 Please configure your mail client to use
authentication.', Port: 25, Secure(SSL): No, Server
Error: 550, Error Number: 0x800CCC79

I've searched the knowledge base but nothing useful has
come up. Any ideas?

Thanks,
Erik

See these links:
http://insideoe.tomsterdam.com/probl...s.htm#550relay
and:
http://support.microsoft.com/default...en-us%3B290808
--
Bruce Hagen
~IB-CA~


"Erik" wrote in message
...
For some reason my brother can't send mail from his
computer. He can receive it, but when trying to send he
gets the following message:

The message could not be sent because one of the
recipients was rejected by the server. The rejected e-
mail address was '.
Subject 'testing', Account: 'pop.earthlink.net',
Server: 'smtpauth.earthlink.net', Protocol: SMTP, Server
Response: '550 Please configure your mail client to use
authentication.', Port: 25, Secure(SSL): No, Server
Error: 550, Error Number: 0x800CCC79

I've searched the knowledge base but nothing useful has
come up. Any ideas?

Thanks,
Erik