We've found that a lot of sudden incompatibilities are caused when something hasn't been updated. Please check the following are up to date and then try to play the game again:
- VR headset
- Windows Mixed Reality for SteamVR
Finally please see if you have any mixed reality add on software installed. We have seen reports of this causing issues with other users, but once they remove the third party software the game works as intended.
A few other things to try that might help:
- Verify the integrity of your game cache using Steam
- Redo the room set up