[Server keeps kicking me]

I've been having issues with my server. Every time I join, the server kicks me. There isn't any error message, the server sends me to the Minehut lobby, and shuts the server down. Is there any fix to this?

[1.17 generation]

Alright, thanks!

[1.17 generation]

While I was playing on my server today, I noticed that the 1.17 generation (like amethyst geodes and deepslate) hasn't actually been found anywhere. Is this a bug or is it not possible yet?