Earlier this morning, I was working with our support team to work out an issue they were having in an environment where Remote Desktop Services had stopped working. Trying to connect to a server via RDS simply failed with a Network Level Authentication warning, strange, given it was a domain environment and everything should be trusted and all good. The issue started life as support seeing Event ID 1058 and Event ID 36870 errors in the event log and they had been looking at https://blogs.technet.microsoft.com/askperf/2014/10/22/rdp-fails-with-event-id-1058-event-36870-with-remote-desktop-session-host-certificate-ssl-communication/ for guidance to this point with no success.
I quickly discovered that a GPO had recently been implemented that enforced NLA for RDS and also assigned a certificate template to use for Remote Desktop instead of the default self-signed version. I hopped onto the certificate authority to check out the certificate template that had been configured and compared it to the recommendations of the Microsoft article for assigning certificates to RDS sessions at https://blogs.technet.microsoft.com/enterprisemobility/2010/04/09/configuring-remote-desktop-certificates/ as this is an article I have referred to before and know it works.