Problems with Compass Calibration

UPDATE: It worked. After almost two hours of various attempts at reducing interference and turning the vehicle around its axes until my neck was stiff, the compass is finally calibrated.

Hello, I am using a TT-02 Chassis by Tamiya with a Pixhawk 4. I have installed the latest ArduRover firmware, and I’m using QGroundControl as a ground control station.

When trying to calibrate the compass, I constantly receive a Mag(0) bad orientation error, causing the calibration to fail.

I have already removed any electronics that could cause interference to the compass, and I am not using the internal compass.

Does anyone have an idea of what is causing the problem?

Thank you already in advance for your help!
Greetings,
Julia