I have an Exchange 2016 server with multiple entries of 2159 pointing to a server removed from active directory long ago. Multiple posts say to use ADSI edit, but this server is no where to be found in ADSI edit.
Here is the event:
Process edgetransport.exe (Transport) (PID=23800). Configuration object CN=OLDSERVERNAME-OLDSERVERNAME,CN=Connections,CN=DOMAIN,CN=Routing Groups,CN=First Administrative Group,CN=Administrative Groups,CN=DOMAIN,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=Domain,DC=local read from OLDSERVERNAME.DOMAIN.local failed validation and will be excluded from the result set. Set event logging level for Validation category to Expert to get additional events about each failure.

