Pixhawk crash AC 3.6.9

Today my hexacopter moved away suddenly and crashed.
At last 10 flight everything was ok.
I checked log but i cant find the reason.
Anyone can help me please?
I attached logs.
Thanks alot.
dataflash log

Your motor2 failed in-flight.
In the log, RCOUT2 goes max, while RCOUT1(The opposite motor) throttle down to keep balance…