Since some months the DFN just publishes a SNAP-version of the easyroam Desktop client. Since it is not working properly (because it's snap… no wonder) and isn't compatible with X11 anymore, the best option is to install easyroam from the official APT repository.

To install the easyroam Desktop client via APT perform the following steps:

1. Grab the key:

    curl -fsSL https://packages.easyroam.de/keys/easyroam.asc | sudo gpg --dearmor -o /etc/apt/keyrings/easyroam.gpg

2. Add the repository:

   echo "deb [signed-by=/etc/apt/keyrings/easyroam.gpg] https://packages.easyroam.de/repos/easyroam-desktop stable main" | sudo tee /etc/apt/sources.list.d/easyroam-desktop.list

3. Update lists:

   sudo apt update

4. Install the client:

   sudo apt install easyroam-desktop