Many thanks Bodini.
I normally do a Ref All Home before anything else. I tried it again, but no joy. The full error message is:
"Machine out of limits for SoftLimit Activation.
I have in config (all mm)
X max 90, min 0, slow zone 1, %20
Y same as above
Z max -50, min 0 slow zone -1, %20
Thanks again for your help.