QuadPlane VTOL - All VTOL motors stopped in flight - Crash


I have a fixed-wing with ICE engine and 4 electric motors for VTOL operation. I was flying today and during the VTOL landing, suddenly all VTOL motors stopped (First PWM=1200 - Spin Min Value, then PWM=1100 - Spin Arm Value). I have checked the log and so far I have not found any reason for that.

I have checked:

Pixhawk board Voltage (Vcc) - Around 4.8-4.95V
Autopilot flight mode: remained in QStabilize
Messages: no Fail Safe alarms
Vibe: Vibration below 20
Gps hdop value below 0.62

Battery voltage also normal.

Does anyone have any idea of what happened?

Thanks in advance,

Post logs… and detailed parts list and how it’s wired

There is a sense of being switched to manual mode.