To resolve the issue where the SuperLive Plus app opens but the screen is black and does not display cameras, follow these step-by-step troubleshooting techniques:

1. Restart the App: Completely close the SuperLive Plus app and reopen it. On Android, you can do this by swiping up from the bottom of the screen (or tapping the recent apps button) to access the app switcher, then swipe the SuperLive Plus app away or tap the 'X' to close it completely.

2. Check Network Connection: Ensure your device has a stable internet connection. A poor Wi-Fi or mobile data connection may lead to connectivity issues with the cameras. You can test this by trying to access other internet-based apps.

3. Reconnect to Camera: Sometimes the app may lose connection to the cameras. Verify the camera devices are online and accessible. In the app, navigate to the camera settings or the server list to re-establish the connection.

4. Clear App Cache: Go to your device settings, navigate to 'Apps', find SuperLive Plus, and select 'Storage'. Here, choose 'Clear Cache'. This can resolve issues related to corrupted cache files that might cause the screen to remain black.

5. Update the App: Check if there is an update available for the SuperLive Plus app. Outdated versions may contain bugs that cause display issues. Visit the Google Play Store, search for SuperLive Plus, and update it if a new version is available.

6. Adjust Camera Settings: If you have access to the camera's settings directly, ensure that the camera’s streaming settings are properly configured. Incorrect settings could lead to a black screen.

7. Reinstall the App: If the problem persists, uninstall SuperLive Plus and then reinstall it from the Google Play Store. This ensures you have a fresh version of the app without potential software issues.

8. Firewall and Router Settings: Check your firewall or router settings as they could block necessary ports used by the SuperLive Plus app. Make sure the required ports for camera connections are open.

For additional visual guidance, you can refer to these instructional videos on fixing the black screen error in the SuperLive app: Watch on YouTube - [learn more] and Watch on YouTube - [learn more].

If none of these steps resolve the issue, consider reaching out to customer support for more advanced troubleshooting.