Unable to connect OpManager to client server using Domain Account (RPC Server is Unavailable).

Unable to connect OpManager to client server using Domain Account (RPC Server is Unavailable).

I have done exhaustive research into this topic, and no solution I have tried thus far has yielded any success. I am attempting to connect a new server to OpsManager, the server was added successfully, but when attempting to have OpsManager connect to the Server and begin monitoring using the Domain Admin Service Account that I have designated, I receive the "RPC Server is Unavailable" error. However, when connecting using ONLY a Local Admin account, it connects just fine and there are no issues. First, I will establish what I have already tried:

- I have verified that traffic is COMPLETELY open between the two servers. Ports are not being blocked, all security is off at this time. 
- I have added the Domain Admin Account to the Local Admin group on the server I am trying to connect to. 
- All relevant services are enabled and running on the Client server. 

I have gone through multiple articles on this website, and have tried any and all steps to resolve this issue, with no luck. My biggest confusion is why a local admin accounts work just fine, but my domain account does not. 

Thank you in advance for your assistance.