This monitor verifies that the domain controller is successfully replicating with all of its inbound replication partners.
If it fails replication for any of its inbound partners AD data could become inconsistent between domain controllers.
Alerts raised indicate that this domain controller has had an issue replicating with one or more of its replication partners.
If the domain controller fails replication for one or more naming contexts in AD, its data (i.e. User/computer accounts and passwords, etc) may become stale and out of date.
This alert could fire while one of the other Domain Controllers in the forest is being rebooted or having maintenance performed on it. This is mitigated by verifying that the DC responds to ping or not but we expect a few false negatives to fire from this monitor.
Log on to the Domain Controller experiencing issues and run diagnostics to help determine why replication failed. The following diagnostic commands are helpful in diagnosing replication failures:
TechNet guide for troubleshooting Active Directory replication problems