DNS or AD Issue - Network connection fails every 0 - 3 hours

After a period of between 0 and 3 hours, network connection is lost. Unable to Ping from the machine to any others with fixed IP addresses on the network. This machine is the DC in a single server environment and acts as a DHCP, File server. Rebooting restores connection. This seemed to have followed an unexpected system shut down and has occurred at least 5 times in the last 40 hours.
Event Log DNS - "The DNS server was unable to complete directory service enumeration of zone SmardenPrimarySchool.local.  This DNS server is configured to use information obtained from Active Directory for this zone and is unable to load the zone without it.  Check that the Active Directory is functioning properly and repeat enumeration of the zone. The extended error debug information (which may be empty) is "". The event data contains the error."

Application Event - "MS DTC could not correctly process a DC Promotion/Demotion event. MS DTC will continue to function and will use the existing security settings. Error Specifics: %1"

System Event - "The Security System detected an authentication error for the server ldap/sma-srv-001.SmardenPrimarySchool.local.  The failure code from authentication protocol Kerberos was "There are currently no logon servers available to service the logon request.
 (0xc000005e)"."