RPC error when setting external URL

I am getting the following error when I try to set the external URL for the Exchange 2013 server that is going to be using this external URL:

error

The task wasn't able to connect to IIS on the server 'PRMTREXCHG.Company.com'. Make sure that the server exists and can be reached from this computer: The RPC server is unavailable.

Does anyone have any ideas as to what can be done to fix this?