Have a good day!
The radio calibration was successful during vehicle setup. However, the pre-flight checklist shows that radio control has something wrong:
Radio Control: No signal or invalid autopilot-RC config. Check RC and console.
I am using QGroundControl and the airframe is VTOL DUO Tailsitter. The receiver was connected to the RCIN. Did I miss anything? Thank you very much for your help.