From this post (https://sopuli.xyz/post/15865566) on !AskMbin@fedia.io
It’s very likely related, but we also figured out that both of debounced’s (the admin of kbin.run) accounts on GitHub and Matrix were deleted last night. So there is a possibility that kbin.run is no more.
Used fedia today, and it looks like they never quite nailed down their 504 problem, so I think I’ll give this one a go for a while.