To prevent car locks from jamming, you need to lubricate them with spray oil from time to time.
Especially if you use the key to open the car, you will need to spray with the straw of the sprayer inside the keyhole.
Repeat this operation for the locks of the other doors and the tailgate as well.
If the door struggles to close
Sometimes you need to slam it hard to get the door closed.
This can be caused by a bad lock setting.
Just check the position of the locking hook applied on the upright in relation to the lock mechanism. Once this is adjusted the problem will be solved.