Old domain is haunting me - Failed to connect to Active Directory

We migrated from 2010 to 2013 with that being said , we also consolidated few forests into 1 main forest so

forestA.forestB,forestC are now all on MainForest - users / email / AD - basically everything.. 

We dont have any mail flow issues however I am getting lots of errors since we shut down the forestA/B/C DC's (active directory).. 

Errors:

•  Failed to connect to the Active Directory in the remote forest forestA.coM

Please check for misconfigurations on the ServiceBinding attribute on the Service Connection Point object CN=ForestA.com,CN=Microsoft Exchange Autodiscover,CN=Services,CN=Configuration,DC=MainForest,DC=com 

Note: Looking at the SCP above in config of AD, it states true that I have two objects: MainForest and ForestA.com ... so my assumption is that I could just delete that object and should be fine? ... Please let me know if thats the case.. 

Error 2:

Process w3wp.exe (OWA) (PID=10016). WCF request (GetServerFromDomainDN DC=forestA.com,DC=com) to the Microsoft Exchange Active Directory Topology service on server (TopologyClientTcpEndpoint (localhost)) failed. Make sure that the service is running