Rover doesn't move in mission mode

Hi everyone, I built a rover but I have problem with the mission mode, when I arm the vehicle it doesn’t move, although no alert message pops up. The mission is composed only of waypoints (no takeoff points) with the height set to 0. By using the MAVLink Inspector I can see that SERVO_OUTPUT_RAW stays constant (1475 us) when I’m in mission mode. I have the same issues with position and hold mode; I move the vehicle by hand but there is no correction from the motors. However, the manual mode works perfectly.

I work with px4 mini and Qgroundcontrol
I am using the master branch of PX4:

System ID : 1

Airframe type : Rover

Firmware version: 1.10.1Beta

I tried the Traxxas Stempede vxl 2wd airframe with the same issues…

Thanks in advance for any help or hints