Pixhawk 2.1 large hexacopter gps red light and wobble

I’ve been trying to get a large hexacopter off the ground using the pixhawk 2.1 and here2 gps for the first time.

The issue I’m facing is that it doesn’t take-off below 40% throttle when as per T/W it should take-off at 30% throttle and when it does, it flew for 30secs after which it went into what seems like auto-land with Here2 flashing red light. I have disabled all failsafe charged the batteries to full and recaliberated the board, but the problem still persists.

If I try arming and flying after auto-land it wobbles and goes out of control.

Post a link to the .bin file flight log.

You mean file from the sd card right?

Yes, it’s on the Sd card. Connect to the flight controller and download it.

00000037.BIN (494 KB) 00000038.BIN (826.2 KB)
I have attached 2 .bin files here from the last two attempts.

In log 38 the battery sagged ~4.5V in the 1st minute which triggered a battery failsafe. Review the log for yourself and look at BAT>Volt. And you are on default parameters, not advisable. Connect to Mission planner hit Alt>A and follow the guidlines and make those parameter changes before another flight.

Thank you for all the help. I solved those issues as per your guidance, but there is another problem that has popped up now.

The Yaw channel is reversed even though i have checked the calibration and the channel settings on mission planner as well as on transmitter. Also the yaw channel is acting like acro mode even though the drone is on stabilize mode. The drone yaws in one particular direction unless given opposite yaw.
Could you help me with this?

Need another log file.