I'm having a problem with external windows directory authentication. I have ACS configured to look in multiple domains (Domain A and Domain B) for users not in its local database. Authentication works for users in Domain A and the ACS server is a member of Domain A. However, users for Domain B fail with an "Internal Error" code in the failed atttempts log. Domains A & B are listed in the available domains. Sniffs of the traffic for both domains from the ACS server appear to show that requests for Domain B are not being forwarded at all to the Domain Controllers.
Any help is appreciated.