Pixhawk not responding to Servo's

I’m facing a problem with the response of servos from pixhawk.
I am using a pixhawk with arduplane 3.5.2 firmware loaded.
I connected the BEC to aux5/6 and a servo to aux1. After arming(solid blue after long beep) the pixhawk when I went to the servo tab on the mission planner screen and used low/high/toggle commands the servo did not give any output.

Also just to check I plugged in my rc receiver to pixhawk and connected a servo to mainout1 and BEC to mainout3. Whenever I made a deflection on the transmitter it was seen on the mission planner screen but the servo did not move a bit.

My servo is in working conditions and also pixhawk power rail has a voltage of 5v.
Please help.