So every day for the past xx months, our server(DC1) are reporting a NTFRS error #13508.
Its giving an error about having trouble replicating with DC2, which is the other domain controller at that site.
It says it has problems with the DNS name of the DC2, which I find weird because they are both DNS server with each other as their primary and themselves as the secondary.
Is this a DNS issue or a DC1 issue, DC1 is running 2008R2 while all the other domain controllers are running 2012 or 2012R2.
What would you recommend I try first
EDIT: i can verify FRS is running on both, and the DNS entries for both servers are fine.
I am also suspicious of our DNS because I plugged in a computer earlier and it took over 2 hours for the DNS entry to replicate from DC3 to DC2
The File Replication Service is having trouble enabling replication from DC2 to DC1 for c:\windows\sysvol\domain using the DNS name DC2.mydomain.com. FRS will keep retrying. Following are some of the reasons you would see this warning.  FRS can not correctly resolve the DNS name DC2.mydomain.com from this computer.  FRS is not running on DC2.mydomain.com.  The topology information in the Active Directory Domain Services for this replica has not yet replicated to all the Domain Controllers. This event log message will appear once per connection, After the problem is fixed you will see another event log message indicating that the connection has been established.