A. 1. Verify that your payment processing settings are correctly configured. Check the payment gateway settings in the app to ensure they match your provider's requirements. 2. Ensure your internet connection is stable, as connectivity issues can affect payment processing. 3. Test the payment process with a small transaction to identify any specific errors or issues.

B. 1. Clear the app cache by uninstalling and reinstalling the app, as this can resolve issues caused by corrupted data. 2. Restart your device to refresh system processes and resolve temporary glitches.