Pixhawk guided mode movement commands

Dear All,

I successfully managed to fly my quad-copter using pixhawk and an onboard computer (RPi). The goto, takeoff and land commands work both on SITL and on the copter. Now, I am trying to give the copter movement commands to track a moving object on the ground. I tried using the send_ned_velocity but the copter is not moving. I tried the same command in SITL running in windows and the copter moves.

Did anyone manage to do this successfully?

Kindly note also that I am running a python script using dronekit after launching mavproxy. All the documentation that I am following are available in the following link:
python.dronekit.io/examples/guid … -demo.html

Thank you!