Hi Dan! The servers seem offline, do you know what happened?
Viewing post in Leaderboard Creator comments
Due to a new browser policy copying to clipboard became broken on some browsers and I am working on fixing it. As a temporary workaround, I made the keys appear on top of the Unity view, so you will be able to copy the keys from there for now. The keys are alternatively printed in the developer console, so you can copy them from there.