The DNS server was unable to open Active Directory. This DNS server is configured to obtain and use information from the directory for this zone and is unable to load the zone without it. Check that the Active Directory is functioning properly and reload the zone. The event data is the error code.

Details
Product:	Windows Operating System
Event ID:	4000
Source:	DNS
Version:	5.2
Symbolic Name:	DNS_EVENT_DS_OPEN_FAILED
Message:	The DNS server was unable to open Active Directory. This DNS server is configured to obtain and use information from the directory for this zone and is unable to load the zone without it. Check that the Active Directory is functioning properly and reload the zone. The event data is the error code.

Explanation
The Active Directory service is not available.

User Action
See article #316685, “Active Directory-Integrated Domain Name Is Not Displayed in DNS Snap-in with Event ID 4000 and 4013 Messages,” in the Microsoft Knowledge Base for more information about this event.