I keep getting a Login Failed error in my ASP.net application when connecting to my SQL Server 2008 database. I am trying to login with the user domain\foo.

When I grant a database login (server and database level) for domain\foo, my application can connect.

When I put domain\foo in a group called domain/goo and give domain\goo a database login, the user domain\foo cannot authenticate.

This does not make any sense. Am I doing something wrong? domain\foo and domain\goo are configured identically. The only difference is that on is a user and one is a group containing a user. Adding active directory groups as users to SQL Server 2008 is supposed to work.