Based on the symptoms described I would verify that you can map a drive to the administrative share of the Exchange server from the Orion server. E.G. \\exchange.domain.ext\C$
The error you are receiving is stating that the something is wrong with the WinRM configuration on that server. Either the certificate was removed, or the WinRM configuration was changed somehow. You can try and verify that on your own by attempting to execute remote PowerShell against that host from the Orion server.
