sometimes you forget to delete the Exchange 2010 CAS Array Object with “Remove-ClientAccessArray” within the Exchange 2010 Shell while migrating to Exchange 2013.
After Deinstallation of Exchange 2010 the “Remove-ClientAccessArray” isn’t available in the Exchange 2013 Shell.
To remove the CAS Array Object open ADSI-Edit and go to configuration
Navigate to this path:
CN=Exchange Administrative Group (FYDIBOHF23SPDLT)
DELETE CAS Array Entry and wait for AD Replication