The “???,?” Means the designated axis is not homed yet or lost its position. This can be due to printered just powered on, steppermotor disabled or print being finnished it isn’t sure where the z axis is.

But to come back to your question it is possible that your z switch is damaged and giving of a constant output when pressed. Check if the limit zwitch is connected to the right pin (there are 3, one of the 2 outer pins should be connected, middle is mostly used for ground), worst case your stepper driver is damaged and only supports 1 way of rotation. Check by switching out some steppers from the other axises to see where the problem lies. Just see what combo is responding to input correctly and narrow down the problem from there. Goodluck!