If you are encountering issues with the UK ETA app being busy and unable to apply, follow these steps for potential resolutions:

1. Check Your Internet Connection: Ensure that you are using a stable and reliable internet connection. A weak connection can cause issues with app functionality.

2. Clear Cache and Data:
- Go to your device's settings.
- Navigate to the Apps section and locate the UK ETA app.
- Select the app and tap on "Clear Cache" and "Clear Data". This can help resolve any bugs or loading issues within the app.

3. Restart Your Device: Sometimes, a simple restart can resolve temporary glitches in apps.

4. Try Again Later: If the app continues to show a "busy" message, it may be experiencing high traffic. Waiting for a while before trying again can often yield better results.

5. Update the App: Make sure you have the latest version of the UK ETA app installed. Check the app store for updates and install them accordingly.

6. Use the Official Website: If the app remains unresponsive, consider applying through the official UK ETA website instead. This alternative can provide a more stable experience during busy periods.

7. Contact Support: If all else fails, reach out to the UK Visas and Immigration support team for assistance. They can provide guidance on any ongoing issues with the app.

It's worth noting that many users have reported similar issues with the app being busy, especially during peak times - learn more.

If you find the app consistently unresponsive, consider sharing your experiences on forums like Reddit to gain insights from other users facing similar issues - learn more.