What generally happens here is that one of your Glentek drives kicked out with a "Current Overload", in fact there will be a lit LED on one of them telling you which one, which in this case is probably the Z axes.
You can reset the drive by pushing the reset button on it or just power the machine down and back-up to reset the drive....
You might also want to make sure you have not governed your drives with the CL Pot on the drive (Current Limiting), they are typically a 3/4 turn POT and you need to have it turned all the way to the right to allow the motors full current capability.
I hope this helps. Good Luck !