Copied out of Bug 480704, since 2024/02/22, Neon Testing, I get: Feb 22 22:47:39 neon-dev systemd[723]: Starting Portal service (GTK/GNOME implementation)... Feb 22 22:47:39 neon-dev unknown[772]: cannot open display: Feb 22 22:47:39 neon-dev systemd[723]: xdg-desktop-portal-gtk.service: Main process exited, code=exited, status=1/FAILURE Feb 22 22:47:39 neon-dev systemd[723]: xdg-desktop-portal-gtk.service: Failed with result 'exit-code'. Feb 22 22:47:39 neon-dev systemd[723]: Failed to start Portal service (GTK/GNOME implementation). Feb 22 22:47:39 neon-dev systemd-coredump[758]: Process 731 (sddm-greeter) of user 119 dumped core. and I don't get an SDDM logon screen. The coredumpctl info is here: https://bugs.kde.org/attachment.cgi?id=166028 This should probably be logged under SDDM, but it seems well hidden :-)
sddm is not a KDE product, reports your be filed at https://github.com/sddm/sddm