Why did my extruder motor stopped working? Before it stopped working, the stepper motor worked very well and didn't show any problem. I experienced this after I fixed a filament problem. The filament got stuck soI retracted to pull the filament out of the heat nozzle. But when I finished this, the extruder didn't work anymore...

I restarted the system but it didn't work. All the motors work fine, even the extruder motor. The A4988 driver has the right voltage at 1.0&nbsp;-&nbsp;1.2&nbsp;V. I have already replaced my RAMPS shield and AtMega board, but it still does not work! I changed the extruder motor to another axis port and it worked good. The voltage input is stable at 11.2&nbsp;V

I can't figure out why the extruder motor is not working for the extruder port?
I have found an answer. So dumb‍♂️‍♂️. It need to heat up nozzle before use extrude or retract command