If a yellobrik-module somehow hooks or seems to need excessive force to plug it into it’s rack-position:

  1. Take it out of the rack.
  2. Use DC-plug of the wall-socket-supply (PSU which is part of the module delivery) and plug / unplug this connector 2-3 times into / out of the module’s DC-socket.

After this treatment the module should fit easily into it’s rack-position.