YouTube may not be working for several common reasons including issues with YouTube’s servers, your internet connection, outdated app or browser software, cache or cookie problems, device glitches, or even incorrect date and time settings. To troubleshoot:

1. Check if YouTube is down using platforms like DownDetector or Google’s Workspace Status Dashboard to rule out server issues.
2. Ensure your internet connection is stable and strong by restarting your router or switching networks.
3. Restart your device to clear temporary glitches.
4. Update the YouTube app, your browser, and your device software to the latest versions.
5. Clear the YouTube app’s cache and cookies to remove corrupted files.
6. Confirm that the date and time on your device are set correctly.
7. Try accessing YouTube on another browser or device to isolate the issue.

If after these steps YouTube is still not working, the problem may be temporary and related to YouTube’s servers, in which case waiting is advised. Following these fixes often resolves most YouTube connectivity and playback problems.