ESC not working?

Hi!, I recently installed a Pixhawk into my F450 that was running a CC3D, and the first few flight attempts resulted in the drone flipping after takeoff. (I found the issue to be wrong wiring of the ESCs to the out ports)

One of my motors then started to not spin up when the rest of the motors were armed. I swapped out the motor but that did not resolve it, so I tried a different ESC. The motor still would not spin, so I then tried plugging the ESC into another receiver and running just that motor with ESC. It spun up, but when I plugged it back into the Pixhawk, no luck. I also swapped which port the ESC was in to see if I somehow fried a main out port?