[Portal 2] Viewports no longer work

[FoudreTeam]

Hello,
After playing Portal 2 outside with Geforce NOW, When I play Portal 2 on my computer Steam Cloud put the same settings from geforce now which get my game to no longer show the viewports (exemple: seeing through portals). I tried to turn off steam cloud and reinstalling the game but I still have the bug, I tried deleting the settings files but still have the bug and after contacting the steam support they said that they don't know how to fix this and they suggested me to post the bug here. I hope someone can help me with this issue.

[misyltoad]

Can you mention your hardware information?

Also try -vulkan as a launch option.