Windows Server 2008 R2 domain

i have 3 DNS servers running with my 3 DC servers. it also hosts DHCP servers. i'm seeing multiple entries of events 4010 and 4013  and upon checking what they mean, it says unable to contact AD DS. to my understanding, AD DS is Active Directory itself and my AD is working (people can login, apps using LDAP are authenticating, etc.,) so i'm not sure how to proceed handling this event ids.

appreciate any help.

i did a dcdiag /test:connectivity. the first half of the output doesn't make sense since i'm connected to the server over the network. firewall is off on all NICs.

Directory Server Diagnosis

Performing initial setup:
   Trying to find home server...
   Home Server = DC01
   * Identified AD Forest.
   Done gathering initial info.

Doing initial required tests

   Testing server: HQ\DC01
      Starting test: Connectivity
         Both IPV4 and IPV6 channels are disabled on all adapter cards of the
         local server. Hence no connectivity to the server.
         Got error while checking LDAP and RPC connectivity. Please check your
         firewall settings.
         ......................... C01 failed test Connectivity

Doing primary tests

   Testing server: HQ\DC01


   Running partition tests on : ForestDnsZones

   Running partition tests on : DomainDnsZones

   Running partition tests on : Schema

   Running partition tests on : Configuration

   Running partition tests on : ACME

   Running enterprise tests on : ACME.com

• Edited by Reno Mardo 28 minutes ago

checking further, i noticed event 1311 also. and upon checking Event ID 1311 there is a single sentence that stands out:

Ensure that adequate site connectivity exists

i did have a single DC in a WAN link that hanged and i have just restarted. maybe this one causes all the errors.

will monitor throughout the day for anymore of this event IDs.