It looks like their servers are struggling with the current load.
If you are curious about Nitrux:
Nitrux is a Linux distribution based on Ubuntu suitable for laptops and desktop computers. Nitrux provides all the benefits of the Ubuntu operating system combined with a focus on portable, redistributable application formats like AppImages. Nitrux uses the LTS branch of Ubuntu as a basis using only the core system and then slowly building up to ensure a clean user experience. Nitrux is suitable for newcomers to Linux as well as *nix experienced users. Nitrux uses KDE Plasma 5 and KDE Applications; we also use our in-house software suite Nomad Desktop adding to the user experience.