Outlook Express error.

[AboutWeb]

I got this error while trying to send a email with Outlook Express. How to fix it ?
The message could not be sent because the server rejected the sender's e-mail address. The sender's e-mail address was '***@*****'. Subject '[*****', Account: 'mail.****', Server: 'mail.****', Protocol: SMTP, Server Response: '550 Access denied - Invalid HELO name (See RFC2821 4.1.1.1)', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC78.

[HTMLBasicTutor]

You would be the sender. Seems your IP might be blocked at the receiver's end.

[daveriddler]

If you are getting a 550 error message, the outgoing mail server cannot verify who you are and will not allow you to send mail. It is best to contact your service provider ensuring you are using them to deliver the mail. Alternatively change you smtp server to another account if you have one (eg gmail)