Hi there! I understand you're having trouble using the Napster app on your device. To get a clearer idea, could you please tell me a bit more about what exactly isn't working? For example, is the app not opening at all, are you unable to log in, or is playback failing? Any error messages you see would also be helpful!

Meanwhile, I can suggest some initial steps to try on your Android 10 WebKit-based device:

1. Restart your device to clear any temporary glitches.
2. Check your internet connection—make sure you have a stable network (Wi-Fi or mobile data).
3. Clear the app cache and data:
- Go to Settings > Apps > Napster.
- Tap on Storage, then Clear Cache and Clear Data.
4. Update the Napster app from the Play Store if an update is available, as updates often fix bugs.
5. Reinstall the app: Uninstall Napster, then reinstall it fresh to clear any corrupted data.
6. Verify your subscription status inside the app, if you can access it.
7. If you are offline, try syncing your playlists again when you have internet.

If you’ve already tried these or if the app is crashing or showing a specific error, please let me know so we can go deeper into solving it. Also, sometimes Napster has temporary network issues on their side, which can be checked at their status page: https://status.napster.com/

Are you able to try these for now? Let me know how it goes!