IIS 5 & IIS 6
POP3 service error: 550 5.7.1 Unable to relay for ....
Last post Jan 13, 2009 04:32 AM by Rouchie
Jan 08, 2009 11:08 AM|Rouchie|LINK
Jan 09, 2009 10:50 AMemail@example.com|LINK
Your error is from SMTP, not POP. And your SMTP server is not configured to allow relaying outside your domain. Check the docs:
Jan 12, 2009 09:57 AM|Rouchie|LINK
Under Relay Restrictions, I have added the IP address of the server itself.
Also 'Allow all computers which successfully authenticate...' is enabled.
Under the Authentication options, I have the following two items enabled:
Integrated Windows Authentication
Jan 12, 2009 04:46 PM|ServerIntellect_BH|LINK
In your Outlook settings, try checking the "My outgoing server (SMTP) requires authentication" checkbox on the "Outgoing Server" tab under "Advanced" options.
Typically a "550 Unable to relay" error indicates the user is not authenticating on the server to send out mail. This would also explain why when testing the email account, you were able to receive a test message to yourself, just not send externally.
Jan 13, 2009 04:32 AM|Rouchie|LINK
Thanks for your reply. This is the most confusing thing about the whole issue - that option is checked in Outlook...!