Send the Picture of the motor Kartal....We got this similar issue, we changed the motor and things have been working good ever since....Encoder of these motors are not readily available...
So if this error is constantly giving issue and is permanently showing....on the non operator side there is a chain and gear inside the cover frame below the motor. Once you open the cover below you would see a chain moving on this gear which has + and - setting on that. What it looks like is...