RoutingMasterDN is pointing to the Deleted Objects container in Active Directory

The other a client noticed the following errors in the Application Event Log in their Exchange 2013 server:

Log Name: Application
Source: MSExchange ADAccess
Date: 3/8/2016 9:44:27 AM
Event ID: 2937
Task Category: Validation
Level: Warning
Keywords: Classic
User: N/A
Computer: xxxxxxxxxxx
Description:
Process edgetransport.exe (Transport) (PID=32144). Object [CN=Exchange Routing Group (DWBGZMFD01QNBJR),CN=Routing Groups,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=xxxxxx,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=xxxxx,DC=xxxxx]. Property [RoutingMasterDN] is set to value [xxxxxxxx
DEL:67729122-b25b-4d4c-b5b0-75ad9e9dacd4], it is pointing to the Deleted Objects container in Active Directory. This property should be fixed as soon as possible.


To correct this problem, we need to use ADSI Edit and navigate to CN=Connections:

In here, right click CN=Exchange Routing Group (DWBGZMFD01QNBJR), go to its properties and find the msExchRoutingMasterDN:

In this particular case, this attribute was pointing to an old Exchange 2010 server that had already been decommissioned. Once I corrected this, and restarted the Transport services, the error went away.