Hey!
That is normal, because each axis search for endstop to find the zero (or home) position. If it doesn’t find then it stops everything and only the communication works. It seems that is the same error with this, UNO/CNC Rotator - Motors Don't Turn - #5 by azisi. You can check the end stop pins either it is connected to correct pins in CNC shield or pins are defined correctly in firmware. 