I have had my Galaxy Tab S4 for about a year. I love it. One annoying aspect is that just like that, auto rotate stops working until I restart it. Usually stuck in portrait, sometimes in landscape. I always go up and check the settings, and it is still set to Auto-Rotate. I've tried turning it off and turning it back on 30 seconds later but that does not work. The only action that resolves it is to restart the tablet. Does anyone have any suggestions on another way to resolve this problem without restarting the tablet.