If you're connecting to an Exchange server (usually in a business
environment), you should report this to your Exchange admin. Sometimes the
fix is as simple as stopping and starting the virtual SMTP server.
If you're connecting to an ISP using POP3, it may be that you need to check
the boxes that say authentication is required for your SMTP server and
provide your password, or you may need to provide your email address instead
of your username or vice versa.

Signature
Kathleen Orland - MVP Outlook
Outlook Tips: http://www.outlook-tips.net/
http://www.howto-outlook.com/
> I'm a new Vista and Outlook 2007 user and when I try to forward or reply to
> an email I frequently get an error "
> 550 5.7.1 Unable to relay for xxxxx@abc.ca
You are trying to send through another smtp server from a foreign account. You need to authenticate.

Signature
Milly Staples [MVP - Outlook]
Post all replies to the group to keep the discussion intact.
After furious head scratching, John asked:
| I'm a new Vista and Outlook 2007 user and when I try to forward or
| reply to an email I frequently get an error "
| 550 5.7.1 Unable to relay for xxxxx@abc.ca
John - 16 Dec 2007 22:52 GMT
how do I do that?

Signature
John Fraser
> You are trying to send through another smtp server from a foreign account. You need to authenticate.
>
> | I'm a new Vista and Outlook 2007 user and when I try to forward or
> | reply to an email I frequently get an error "
> | 550 5.7.1 Unable to relay for xxxxx@abc.ca