Why i cannot use my sketchup if my other pc is off?
Turning off a PC does not sign you out from your subscription. You should be able to sign in on two PCs, but each version of SketchUp you’re signed into counts. If you have older versions of SketchUp still on your PCs, open them and make sure you are signed out. That would free up the sign ins to be used by SketchUp 2023.