Thank you for the response! I didn't have time to look into this yet. But there is more going on with the system I think. WIFI also doesn't work anymore. And after trying to solve the WIFI, the ADB of the VOXL stopped working. So we for now we are using a different VOXL.
Something else we are running against is the message Reject position control, with working VOXL CAM systems installed on our drones. When we fly everything is super! When we land, after the drone has bumped into things while flying (drone is collision proof) or when heavy wind was pushing it. We cannot take off after landing, it will display Reject position control. Only when the we connect a laptop to the QGC, we can hear that the VOXL reboots and then the Reject position control is gone, and we can go fly again. But if we use QGC via the PX4 Telemetry port, this doesn't happen, and we need to unplug and replug the battery to be able to get the Reject position control message away again.
We don't really know why this happens and how we can solve this. It would of course be great if the VOXL didn't need to reboot in order the drone can fly again in position mode. But it already would be helpful that the VOXL would reboot without having to have WIFI connection with QGC. Please help!