Error with the DNS when trying to add a user under User Management

I am getting the following error when I click on the Add User or Group.  I have added to this group before and the DNS checks out.

Directory browse error while loading directory view

Reason:  Unable to obtain DNS hostname of Active Directory domain controller

with ntdsa object name "CN=NTDS Settings,CN=CCS-DC2,CN=Servers,CN=Default-First-Site-Name,

CN=Sites,CN=Configuration,DC=hsig,DC=comm".

Thanks for any assistance with this that you can give.

Cathy