Outlook over RPC not accepting username/password

[johnaau]

We have been running SBS 2003 with several users accessing email remotely through Outlook 2003 and 2007 for many years but recently all users are reporting Outlook is constantly asking for username/password and not accepting even though the username/password works elsewhere including Outlook web mail.

We have a self-signed certificate and this has been added to trusted certificates on each users computer.

There were some possible changes made around this time. All users passwords were changed (but as I said the correct password is being used), and the SBS 2003 connect to internet wizard was run to change to use a smarthost. Im not sure if these are related, but did happen around the same time as the problem started.

As I said it all worked fine for years. No changes made to clients email config and effecting all users so must be a server issue.

I am not sure how to diagnose this issue or what the possible causes are, greatful for any help.

 

[johnaau]

I ran the Exchange connectivity test (had to buy a trusted certificate first) and it said that NTLM authorisation failed. I enabled Windows Authentication in IIS for the RPC folder and it is now working.