What about the sliding door slot?

When the sliding door is not aligned with the groove, it means that the upper and lower slides have deviated from the track. In this case, the sliding door will naturally not move, so let the pulley slide to minimize friction.

Clean chute

The first thing you have to do is to clean up the smooth stains.

Check the contact between the slider and pulley.

After the slideway is cleaned, check whether there is anything between the slideway and the pulley to block the contact, so as to increase the friction between them, such as plastic paper similar to transparent tape, or some places where the skin has exploded. If there is, clean up all the sundries.