In the alley near Hannek there is a magnet board where you can move the magnets around. There is an annoying bug that causes the magnets to lock into their places and you cannot move them anymore after doing it once. This bug is reported at the game Steam community.
My suggestion is to always save your game before you fiddle with the magnet board and then immediately load the saved game after that. When you know what you are doing with the magnet board you set the magnets in correct position on the first go. The correct position is found in this guide but don't click that link if you don't want to know what puzzle the magnet board is part of.
This Steam community post describes how you can fix the problem by editing your game save file. Remember to backup before editing save files!
This hint was added here from a feedback from a guide user. Give me feedback to improve these guides.