Copter shutting down (failsafe?), pixhawk has an orange blinking light but volt tester is showing charged values.

I’m completely new to this, but I’m trying to do a test flight. I assembled everything and I think my battery is fully charged (adapter does still keep indicates charging when plugged in). When I connect the battery, then my pixhawk generates an orange blinking light and shutsdown the propellers. When I checked the logs it’s due to the battery low voltage. But my voltage meter indicator keeps saying 12,5V and around 4.2V per cell. Do I have a bad battery, charger or is my pixhawk broken ? I have no idea which part is broken? Or even if there is a part broken or I missed some config.

Logs

BAT, 55910520, 1.452039, 1.680851, 3.431681, 46.52869, 0.06581409, 0, 0.06667614

POWR, 55910541, 4.490771, 4.498, 0, 6

MSG, 55910598, Battery 1 is critical 1.45V used 47 mAh

Mission planner

Seems to not registrate any voltage (displays 10V)

Build:

Frame: HAWK’S WORK F450 Quadcopter Frame (450mm wheelbase)

Autopilot: Pixhawk 2.4.8 Flight Controller

GPS Module: Ublox M8N GPS with integrated compass

Compass: External compass integrated with GPS module

Power Module: Standard 3DR-style power module (XT60 input, voltage/current sensing)

Radio System: 2.4GHz RC Transmitter & Receiver (FlySky)

ESCs: 30A Brushless ESCs

Motors: 920KV Brushless Motors

Propellers: 10x4.5 inch

Battery: 3S LiPo, 11.1V, 4200mAh