Hi, I just had the same issue. I went through the known issues here:
https://help.autodesk.com/view/RVT/2024/ENU/?guid=GUID-BDD6303D-063C-4B1D-B3B1-6783137FFFD0
My issue was ’ Twinmotion commands are enabled but not functional’
The registry key Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\EpicGames\Unreal Engine\RevitEngineDir was missing.
Also, the value they mention on the page was not correct for me, I had to use this:
C:\Program Files\Epic Games\Twinmotion2023.2EDU\Engine
So adding that key to the registry with the path to your Tinmotion installation Engine should work