We have an issue with one of our domain controllers, let's name it "DC_A". This domain controller is a Windows Server 2008 R2 and is the operations master of our domain. Problems we get are the following:
- The DNS on the server does not work. When we try to open the DNS Manager it gives the following error: "Access was denied. Would you like to add it anyway?". Answering yes displays the DNS Manager with a red X on the domain controller.
- If you open "Operations Master" from Active Directory Users and Computers management console from another domain controller, the operations master field displays "ERROR" for RID, PDC and Infrastructure. This field should show DC_A as the operations master. If you check this from DC_A it correctly shows itself as the operations master.
- All systems that have DC_A as their primary DNS cannot authenticate to active directory and fail to login.
The server started giving these errors without any change to its configuration from our side. What could be the problem causing these issues and how can we troubleshoot?