Cant Calibrate Radio on QGC to FS-iA6B

Hi all.

I am in the process of using a Pixhawk 2.4.8 and connecting it via my MacBook Air to QGC. I am in the middle of my Radio calibration when I get the error Detected 0 Radio Channels, To Operate PX4 you need at least 5 channels.

Can anybody help with my issue?

I have a cable from RC IN on my pixhawk going to the FS -iA6B receiver i-bus servo port. My transmitter is a FS-i6X