My Unity scene is gray and doesn't work

I was playtesting my game and when I exit game view my scene is completely gray and I have an error saying ArgumentNullException: Value cannot be null and a text box with an exclamation mark saying can't add UniversalAdditionalCameraData to SceneCamera because UniversalAdditionalCameraData is already added to the game object!

I can select things rotate the camera and do everything but I can only see gray. I already tried resetting the layout but it doesn't work