I just tried your code and it worked perfect for me. I’d assume its something with your frame object itself, if not you can try adding a task.wait before you play the tween to make sure your loaded in before it plays.
Actually, I think problem might be because because your referencing the object by using game.StarterGui. I’m not sure where your script is, but if its in the loadingscreen ScreenGui you should just do local object = script.Parent.Frame or whatever the path to your frame is.