What does the error code M126 indicate?

What are the PLC2 addresses X0 and X2?

What is the KM-ASSYM2-02 error id of 57?

What is the origin sensor error described as abnormality?
The solution for M126-Nozzle 1&2-Z axis origin sensor abnormality (PLC2-X0, X2) involves calibrating the Z-axis sensors and adjusting the nozzle