How do I control Pixhawk 2.4.8 with a Radio Controller

Hi all,
I’m very new with pixhawk (Pixhawk 2.4.8), and trying to get it to fly using my FlySky FS-I6 radio controller via a FS-IA6B receiver. I’m not sure if I set it up correctly but the pixhawk keep going from armed to unarmed (I noticed that the main LED light flashes blue while unarmed and solid blue while it’s armed).

My current set up is that I have my receiver plugged in the RCIN port of the pixhawk with my radio controller set up to communicate PPM (I successfully calibrated my radio control in QGroundControl). I can armed the pixhawk with the SWD switch on the radio controller, which will briefly armed the pixhawk for roughly about 10seconds before it start flashing green and unarmed itself.

I’m not sure where I’m going wrong, but any guidance or feedback would be greatly appreciated.

This picture show the pixhawk with a solidblue light when it’s armed. (I don’t have the arm switch and buzzer plugin for majority of my experience/testing, just in this picture to get some audio cue and maybe the arm switch would some how fix my problem)

And this is my QGroundControl Flight tab