Pixhawk 4 - ARMED, takeoff/landing detected but motors don't spin

I’ve done the transmitter setup and calibrated ESC’s within QGroundControl. I try to apply throttle in Stabilize mode, it shows “Takeoff Detected” in QGC but no motor spin. What could be my issue?

Here’s what I’m working with

Software: QGroundControl

Motors: ECO5330C-V2 series brushless outrunners 280KV
http://shop.dualsky.com/eco5330c-v2-series-brushless-outrunners_p0285.html

ESCs: PCU 80HV, PCU series brushless drive unit for UAV
http://shop.dualsky.com/pcu-80hv-pcu-series-brushless-drive-unit-for-uav_p0354.html

Transmitter: Taranis X9D Plus

Receiver: FrSky X4RSB 3/16CH Telemetry Receiver with Futaba SBUS 16 Channels Smart Port

Batteries: 9S Configuration, 8000mAh 100C

Here’s a suggestion (it may work or not): try to upload another firmware version (better yet, use a stable version). If you still notice this problem, I would take a look in your wiring if I were in your shoes.