Symptoms
When a user starts the Site Builder and clicks the Login button, the user may receive the following error message:

The server threw an exception
Resolution
If the user who is trying to log on does not have access to the root of the domain (that is, if the user does not have Read access for Users and Groups), Content Management Server (CMS) does not impersonate the System account user for CMS for this group membership enumeration, so the user cannot enumerate the group membership and receives an exception error message from the domain.
Note that this is not a problem when Active Directory Service (ADS) Lightweight Directory Access Protocol (LDAP) authentication is enabled. Impersonation with the System account user works correctly when ADS LDAP authentication is enabled.