Machine HOME on Stepcraft2 (600) not working

I have just built my first CNC - a stepcraft2 (600). I have installed UCCNC and the stepcraft UCCNC software for the 600. The "First Step" documentation says I need to Home the machine. The Z axis is the first axis to operate but it doesn't know when to stop!! When I hit the HOME ALL button, the z axis rises, hits the x axis gantry but tries to keep going. The motor grinds and the UCCNC display shows the x-axis is still rising to fictional measurements. I have to hit the Cycle Stop button to stop it. Because I can't get past the z axis, I can only assume the x and y axis will do the same. Am I doing something wrong? Are there settings I need to change to make it work correctly? The limit switches all "click" when I press them manually but only the y axis switch lights up the diagnostics and sets off the RESET alarm. I have checked the wiring and all looks OK as far as I can see, but shouldn't the x and z axis light up the diagnostics as well? I feel like I'm not understanding the software requirements within UCCNC and the First Steps documentation is not telling me what I need to know.

Apologies for not writing in German, but I haven't written in German since I went to school 30 years ago. I would be grateful for any help

Craig Turner (Ireland)