Pixhawk works but motor's won't turn

We recently finished building our PCC and Jetson. Before adding those to the AVR, it flew just fine. Now that we have added those parts, we can’t get the motors to turn. The PCC lights up, but the Jetson does not. The Pixhawk controller lights are all on as well. I have tried running the motors through QGC, but still no luck.
Has anyone encountered this error before? Any tips on how to troubleshoot?