If you get The DNS server has encountered a critical error from the Active Directory in the event log, as listed below:
Event Log: DNS Server
Event ID: 4015
The DNS server has encountered a critical error from the Active Directory. Check that the Active Directory is functioning properly. The extended error debug information (which may be empty) is “”. The event data contains the error.
This is typically caused by a poor connection between replicating DNS servers, possibly you have a VPN between servers that it’s quite up to scratch.