Cognos with IIS login issues

[jeremywv]

We have recently began using Cognos with IIS and AD for authentication.  We have internal and external users.  For external, we're using a reverse proxy thru our hosting provider to lock down the traffic for external users.  I am currently using basic authentication in IIS.

Currently internal users are fine.  However, externals are having an issue.   After putting in credentials and logging in, it seems to be logging in, but then I just have a spinning circle and the page seems to be refreshing every few seconds but never goes into Cognos.  Has anyone experienced this?