To resolve the issue of not being able to sign up for the Plus subscription on your Android device with the Insight Timer app, follow these actionable steps:

1. Check for App Updates:
- Open the Google Play Store on your Android device.
- Search for "Insight Timer".
- If an update is available, tap "Update" to install the latest version.

2. Clear Cache and Data:
- Go to your device's Settings.
- Tap on Apps & notifications.
- Find and select Insight Timer from the list.
- Tap on Storage.
- First, tap Clear Cache, then tap Clear Data.

3. Restart Your Device:
- Completely power off your Android device.
- Wait for about 30 seconds, then turn it back on.

4. Reinstall the App:
- Go to the Settings > Apps & notifications > Insight Timer.
- Tap on Uninstall.
- After uninstallation is complete, go back to the Google Play Store and search for Insight Timer and install it again.

5. Check Your Internet Connection:
- Ensure you're on a stable Wi-Fi connection, as any interruptions may lead to looping issues during sign-up.

6. Try Signing Up Again:
- Open the app and navigate to the Plus subscription section.
- Follow the prompts to input your payment information and sign up.

7. Use the Website for Subscription:
- If the app continues to loop, try signing up through the website:
- Visit the Insight Timer website and log in to your account.
- Navigate to the Courses page and click on any course to access subscription options - learn more - learn more.

8. Contact Support:
- If problems persist, consider reaching out to Insight Timer support for further assistance. They may provide specific guidance regarding account-related issues or technical problems - learn more.

Following these steps should help you successfully sign up for the Plus subscription. If you encounter additional issues, documentation and community forums may offer further insights.