Wilsonjiaho, thank you for your post. The door hinge bushings WP34001192 may need to be inspected to identify if they are missing or damaged. They are located where the hinge connects into the door. To access this area, the hinge and door would need to be removed from the washer. From there, the face of the door can be set on a flat surface and towel, then the inner trim removed. If the bushings are damaged or missing, the missing/damaged amount would need to be replaced.

It may be possible that the hinge mount on the frame could be misaligned. If the hinge screws are loosened at the front panel and the hinge rotated to allow for a better alignment, it may shift just enough to better seat.

I personally have not seen a door become worn enough to sag, however, that is due to most of what I have seen is due to heavy items being hung on a door or a child swinging on the door. In saying that, it is very much possible for the spacing where the hinge sits to become worn over time. Unfortunately, it appears the manufacturer has discontinued both the frame WP34001424 and the glass holder WP34001426.