Installation of WESCO Built-in Waste bin in door

Fitting instructions for WESCO rubbish bin in the door.
Anleitung zur Installation/Montage vom Tür-Einbau-Midtkübel.
I managed to get the door closed fully by adjusting the screws of the door hinges.
I don't understand why the pin in the railing isn't as broad as the railing, as the space causes it to bang to its sides...