​Root Cause: Communication failure between cloud link and telemetry link (one of the links cannot establish connection).

​Troubleshooting Steps:

• ​Cloud Link Issues:
  1. Check remote controller port 4G network status.
  2. Verify drone-end 4G network connectivity.
  3. Confirm backend server availability.
• ​Telemetry Link Issues:
  1. Test 2.4GHz telemetry signal between controller and aircraft.
  2. Ensure both devices are within ​2.5km line-of-sight range.
• ​Resolution: Confirm both links are operational before proceeding.