delta printer - calibration problem

Hi all,
Does anyone know by chance how to solve this problem with the calibration:

Object is a square of side 50 mm size.

It seems that one axis is not operating properly (even if strange it is all are done in exactly the same)
Any idea what would cause that?
I thought that perhaps the spectra line that is used could be wrong on the axis.
There are options in repetier host firmware to set different steps for the various axes?
Because when I was changing
     # define XAXIS_STEPS_PER_MM AXIS_STEPS_PER_MM
     # define YAXIS_STEPS_PER_MM AXIS_STEPS_PER_MM
     # define ZAXIS_STEPS_PER_MM AXIS_STEPS_PER_MM
so it always affected all axes are the same.
Thanks for your help.