Okuma Alarm-D 4686 MCS Rotary encoder 4 error

Okuma Alarm-D 4686 MCS Rotary encoder 4 error
Illegal data was detected in Rotary encoder 4(HEIDENHAIN).

Object
Axis

Character-string
None

Probable Faulty Locations
Rotary encoder 4(HEIDENHAIN).

Corrective Action
Change Rotary encoder 4(HEIDENHAIN).