Standard Plane, Servo outputs not giving any Output. Stuck!

I am certain I have wired everything up correctly and my servo is getting 5V (it auto takes its last trimmed position when I plug in my battery on the servo rail) but it does not react to any input from my radio whatsoever. I have even made sure the vehicle is prearmed through the parameters. The only way I have been able to get my servo to react to any input from the radio is using the AUX1 or AUX2 channels I can configure to any channel, but of course this is not enough since the standard plane has 4 control surfaces and the autopilot doesn’t recognize the 2 configurable AUX channels as a control surface. My radio is the RadioLink AT9S, I am using the Pixhawk 4 with the PM-07 board, and lastly I am using QGroundControl as my software. Really don’t know what to do anymore.