You are mounting the cables on the machine's frame but when plugging them onto the motor, you notice that 1 XLR connector is not able to reach the control unit.
You want to see the indicators lights for the limit sensors and the inputs (Z probe, enclosure...) to check if they are working properly, but PlanetCNC does not display this information by default.
All operations are frozen. The machine won't move and there is a blue square around the Emergency Stop icon in Planet CNC (meaning it is activated and locks the machine).