Maintenance work

Links
- https://www.ulb.uni-bonn.de/en/news/08-29-2022-restricted-network-access/colourbox12613110.jpg/image_view_fullscreen
- https://www.ulb.uni-bonn.de/en/news/08-29-2022-restricted-network-access/colourbox12613110.jpg/@@download/image/COLOURBOX12613110.jpg