What is the M126-Nozzle 1&2 Z axis origin sensor abnormality (PLC2-X0, X1) error code and what does it indicate?

What machine code KM-ASSYM3-05 is and how is it related to the
The solution for the M126 error involving nozzle 1&2 Z axis origin sensor abnormality in a PLC2-X0, X1 system might require calibration, maintenance, or replacement of the Z axis origin