So interesting issues. I had some backup copy jobs fail with the following error.
Date/Time :: Unable to access target repository Error: The RPC server is unavailable.
RPC function call failed. Function name: [GetSvcVersion]. Target machine: [IPADDRESS].
It would try 6 times and then fail. This is to a rebuilt backup repository that I use at another site for backup copy jobs only.
The new system is Windows 2016 and was a clean install.
Some research led me to this KB. https://www.veeam.com/kb1174
None of the solutions resolved my issue so I treated it like a Microsoft issue.
As it turns out the NetLogon service was set to manual and not started. I set this to automatic and started the service and the issue was resolved.