A. 1. Force stop the app: Go to Settings > Apps > Oxygen Advantage and tap on 'Force Stop'. Then reopen the app to see if it resolves the issue. 2. Clear app cache: Navigate to Settings > Apps > Oxygen Advantage > Storage > Clear Cache. This can help if the black screen is caused by corrupted cache data.

B. 3. Check for device compatibility: Ensure that your device meets the minimum requirements for the app. If your device is outdated, consider upgrading to a newer model.