Rover servo not working

Greeting. Hope you all are keeling safe in these crazy times. I have a problem with pixhawk 2.4.8. Its from aliexpress. It had been sitting in the drawer as I had given up a couple of years back. With the covid situation its a good time to get the kids involved.
So,
Its setup as a rover.
I cant get the servo to work. (Servo works fine generally)

I’m using a separate ubec for powering the servo rail.

In mission planner and qground control the radio is signal is registering. Using spectrum satellite rx.

In the ‘servo output’ in MP the transmitter stick is not reflecting any movement on throttle or servo.

The servo does a micro movement when the rover is connected or armed.
The rover arms alright.

Any help troubleshooting this would be appriciated.