Can’t send emails to certain addresses

I have set up a email account in Outlook 2002Your message did not reach some or all of the intended recipients.

Subject: RE: Please confirm your BBCi registration
Sent: 22/03/2003 17:39

The following recipient(s) could not be reached:

’email.validation@bbc.co.uk’ on 22/03/2003 17:39
550 relaying mail to bbc.co.uk is not allowedYour message did not reach some or all of the intended recipients.

Subject: RE: Please confirm your BBCi registration Sent: 22/03/2003 17:39

The following recipient(s) could not be reached:

’email.validation@bbc.co.uk’ on 22/03/2003 17:39
550 relaying mail to bbc.co.uk is not allowed”

Any help would be very much appreciated.

Thanks
Wayne