Since June 2019 you will need an eduroam profile signed by the new root certificate of the German Telekom. You can find the pre-configiured profiles on this link https//cat.eduroam.org
Or you will just want to follow the link undert this QR code:
Please find a more detailed despription on our intranet (for authorised users only).
Please note: Should your Mac Book still run MacOSX El Capitan or older, a different profile is required. Please contact the IT at the institute