Dcom errors should be unrelated. If replication fails there should be errors recorded in the event log. Not sure what you're seeing but you could try a non authoritative sync. If using older FRS you can follow along here.
https://support.microsoft.com/en-us/help/290762/using-the-burflags-registry-key-to-reinitialize-file-replication-servi
or for DFSR follow along here.
https://support.microsoft.com/en-us/help/2218556/how-to-force-an-authoritative-and-non-authoritative-synchronization-fo
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