It seems that the 12V power overpassed the transistor and went directly into the motor.
Soldering Motor - Driver with long pin headers.
The code is running, the Arduino is powered up, and the motor is running.
However, the motor didn’t run when connected to the H-bridge.
After reading the voltage value through the H-bridge, I got a value of 0, so I probably ruined the H-bridge during the soldering process.