I am working with a new installation of TFS2012 and after working within a project collection for a bit I went into the Admin Console to change the group membership. Clicking on the Group Membership or Administer Security links within the Admin Console results in an error:
The request was rejected by the server. HTTP code 400: Bad Request
I've verified and reapplied both the service account permissions and the Admin Console Users permissions with no luck. I can, however, configure the security via the web based control panel for the collection.
Anyone have ideas of the possible cause?