https://kb.parallels.com/en/123861
KB Parallels: RD Session Host Agent is not verified
Windows has failed to register the RD Session Host Agent service.
rd session hostkb parallels
https://kb.parallels.com/en/125099
KB Parallels: How to deploy RAS RD Session Host Agents using Powershell module
Prior to using a script, the following information must be known:
rd session hostkb parallels