I have a client that has two domain controllers. When rebooting the PDC, we noticed that access to the Exchange server would stop. Traced the issue back to a GC not being found problem. Added the second DC to be a GC (it’s not recommended to have the Infrastructure Owner be a Global Catalog server, but with only 2 servers to play with…) so that the user systems would be able to use secondary DNS.

But then I noticed in the eventviewer that we were receiving an error:
Replication Failure: The reason is: The source server is currently rejecting replication requests.
Not good.
You can find out the exact error easier by going to Start >> Run >> replmon. Add your entire domain to the list, then expand out the servername. You’ll see red x’s on the non-replicating servers. Click on one of those red x’s to see the exact logs.

The fix:
In a command window, type:
repadmin /options SERVERNAME -DISABLE_INBOUND_REPL
repadmin /options SERVERNAME -DISABLE_OUTBOUND_REPL
The “-” is very important in this instance. It removes the restrictions. + would therefore add the restrictions.