Throttle is not working when autonomous mode

Hi. I have a problem. I’m using qgroundcontroller for my fixed wing aircraft. I can use the UAV with manuel mode when pixhawk is connecting via RFD telemetry but When I try to update new mission, I have tried takeoff, loiter or just waypoint, the throttle is always zero, motor is not working. I have tried to move UAV up and down, the servos is working properly in mission mode but motor is not. So What is the problem? How can I fix this? Can you give me any suggestion about that issue?

Have a look at this:

And check in which takeoff/launch mode it is.