I already glued GPS on Pixhawk, how could there still be EKF Yaw Error

The preflight check always says mag field fail, EKF Yaw Fail, something like that, I checked the doc, says, the difference between GPS compass and Pixhawk compass should be small, so I glued these two together and did all those calibrations, and the calibration do show all green light, but I just cannot arm, always get the EKF yaw error. Please help me out, driving me crazy now. Thanks!

What’s your setup? Autopilot, compass/gps, vehicle, PX4 version, etc.

I would also try PX4 master (flash under advanced in QGC) and post the log to https://logs.px4.io/.