Error 503 - Outlook 2007 V's Mr Site V's Sky Boradband!!

[Stu007]

Hi,

I'm really hoping someone can help me with this problem:

I have a Mr Site email address, I'm trying to make it work with outlook 2007 and I'm using Sky Boradband. I can not or the life of me get it all to work happily. I've had various error messages but now I'm getting this error message as a reply email

Your message did not reach some or all of the intended recipients.

Subject: RE: XXXXXX
Sent: 03/07/2010 01:38

The following recipient(s) cannot be reached:

'XXXXXXXX XXXXXX' on 03/07/2010 01:39
503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server.

Please can someone give me some advice!!

Thanks!!

[Lusiphur]

For starters the error "503 This mail server requires authentication when attempting to send to a non-local e-mail address." generally indicates that you need to be using UN/PW authentication to log into the SMTP server to send email outside your own domain.

"Your message did not reach some or all of the intended recipients." can be caused by a number of issues ranging from mail servers rejecting the message due to untrusted mail server on your end to mail delivery issues in general.

Overall it sounds like the mail server simply wants you to log in before sending mail to outside recipients and that should solve the issue so change authentication setting on your SMTP server setting to include your account username and password and you should be fine.

That being said... I fail to see how an issue with a 3rd party mail service not working in Outlook 2007 has anything at all to do with ASP.Net lol :P