App problems on android version

When I want to listen to a playlist with both the screen on and off on YouTube, after a certain period of time it shows me: the video clip has been interrupted. Even if I watch a video clip on YouTube for 5 minutes, my screen turns off even though a video clip is playing. Lately I’ve started having problems with open tabs. For example, I go to a site, close the app, and when I open the app again, it doesn’t pick up where I left off.What should I do to solve these problems?