Autodesk Revit 2021 start up message “The License Manager is not functioning or is improperly instal…

I have a owned fully functioning 2021 Building Design Suite Premium.

I have been using the Revit program for years and it now give this message:

“The License Manager is not functioning or is improperly installed. Revit will shut down now.”

Support has sent me on a wild goose chase of dead end solutions that include:

AdskLicensingInstaller-win-16.0.3.14414 

AdskLicensingSigninHelper-2.5.0.1441-win

What is the solution to this?