Extruder skipping most probably causing by:
1) Printing speed too fast, nozzle not hot enough
Try slow down printing speed and increase temperature on nozzle.
2) Skip during printing the first layer
It could be the bed leveling issue, the nozzle is too close to the bed and block the extrusion, causing the extruder motor skipping.
3) Clog Nozzle or PTFE tube
Replace one should help.
4) Heat Creep
Check the hotend 4010 cooling fan, if it is not function properly, it can cause the heat creep, filament will melt and stuck in there. Clean the hotend heat sink, change PTFE tube, replace the hotend 4010 cooling fan should help.
5) Dust or debris trapped in the extruder gear
Clean the gear should help.
6) Gear slip from the stepper motor axle
Tighten the grup screws on the gear shoujld help.
7) Extruder bearing rusted and not turning when extruding
You can try clean it with WD40, but it’s unlikely to be cleaned entirely, replace one will be easier.
8) Filament tangled
It happens when you keep the filament without clipping the end of the filament properly. A small binder clip can help prevent this issue.
9) Stepper motor cable connection issue or broken
Rare case. Check all issue above if it still having issue, this could be the cause. To diagnose, you can try swap cable temporary with other stepper motor and do a test, if it fix the issue then a replacement for that particular cable will be needed.
Let us know if you have encounter any other causes and how you fix it in the comments. Thank you!