The adapter is supposed to be printed without supports. I used PETG and 0.2mm layer height and this worked flawlessly for me. I printed a second one, where I adjusted the angle so the jar is parallel to the front of the dispenser. This was a request of my inner monk.
The candy dispenser I printed is this one:
https://www.printables.com/de/model/274646-nutella-jar-candy-dispenser
Have fun!
The author marked this model as their own original creation.