Dji phantom 4constantly  beeping, no lights under motor. DJI GO App says aircraft disconnected

Im not sure if this is a problem with a mainboard

Hello, there. Sorry for your inconvenience. Would you please perform the troubleshooting steps below to have a check?
1. Confirm that the remote controller and the aircraft have been powered on.

Press the Power Button once and then press again and hold to power on the remote controller. The product gives a prompt sound when successfully powered on.

2. Remove the microSD card and try again.

3. Switch the linking method between “Linking with app” and “Linking with combination buttons”.

4. If it is invalid, check whether the remote controller has been updated to the latest version. Connect the remote controller to the app. After the connection is successful, check whether there is a prompt to update the firmware. If yes, update the firmware to the latest version and try linking again.

5. If the linking still fails, check whether the aircraft firmware has been updated to the latest version. Connect DJI Assistant 2 and check the version. Update to the latest version and try linking.

6. If the issue persists, please record the linking process for us to further verify the issue.