YouTube videos may not be working due to a variety of reasons including issues with your web browser, internet connection problems, or bugs with the YouTube app or service. Common causes include browser glitches, slow or disconnected internet, outdated apps or operating systems, and issues with device cache or cookies. Solutions involve refreshing or restarting the page or app, trying a different web browser, clearing browser cache and cookies, updating or reinstalling the app or browser, lowering video quality for smoother streaming, and checking internet connectivity. In some cases, videos might be unavailable due to regional restrictions, removal by uploaders, or age restrictions. If the problem persists across devices, it is often related to internet or YouTube service issues. Checking your internet speed, restarting your device, and ensuring all software is updated can usually resolve most playback problems.