Using SBS2003 as a POP3 server for remote clients

Today I worked on an issue where external POP3 clients (Outlook Express in this scenario) were not able to authenticate to the SBS POP3 service.  They would get repeatedly prompted for username/password.  Funny thing was that a new user called "test" worked fine.  The problem was the syntax of the username as described in https://support.microsoft.com/?id=326995.

Thus "test" worked because the username/logon name/Exchange alias all matched!

 

Petergal