Hi there! I see you’re running into an issue with WatchTube on your iPhone where the message says the app data couldn’t be read. Could you tell me a bit more about when this error pops up? For example, does it happen when you open the app, try to load a video, or during login? That info will help me guide you better.

Meanwhile, based on what I know and have seen reported, a common root cause is corrupted or outdated app data that the app can’t interpret correctly on your device. Since you mentioned iOS 11.0, it’s an older version, which sometimes might affect compatibility.

Here are some steps we can try to fix this:

1. Restart the iPhone: It sounds simple, but sometimes a quick reboot clears up temporary glitches.

2. Delete and reinstall the WatchTube app: This clears out old cached data and might fix formatting issues with stored files causing the error. To do this:
- Tap and hold the WatchTube app icon
- Select “Delete App” and confirm
- Open the App Store, search “WatchTube” and download it again

3. Check your internet connection: Sometimes poor or interrupted connections cause incomplete data downloads, leading to read errors.

4. Try switching WatchTube server instances: Within the app, go to “Settings” → “Instance” and pick a different server if available. The servers deliver content slightly differently, and switching might avoid corrupted responses.

5. Update iOS if possible: If your iPhone can upgrade beyond 11.0, updating might improve app compatibility and reduce errors.

If you've already tried these or it still persists, let me know exactly when it happens, and we can dive deeper into the issue—like looking at app logs or checking if there’s a temporary server problem.

Are you able to try these steps? Let me know if you need help with any of them!