I installed clumps on my server and it crashed on startup. After looking at closed issues I made sure the server was on version 12.8.
Here is the log https://paste.shockbyte.com/desofodanepagovikofa
I usually run the server with a few performance mods like lithium but for clarity I removed them on this startup.

Interestingly when I tried to create a server with clumps on my own pc it worked flawlessly. I have no idea why. The remote server keeps crashing however.

What java version is the server running on?

Exact version and distribution please

I think if you try and re-install fabric from https://fabricmc.net/use/ on the server it will work

Apparently it just works now. I tried to use the newest server again, as you said. I am even more confused now as I tried exactly that with the same server version and everything just 10 hours ago after I read the closed tickets and it did nothing. That's why I made the server on my own pc to begin with.

Anyway thanks for your time and for making this mod.

It seems to be something to do with Fabric, it doesn't think Java 17 is actually Java 17, while I could fix it on my side by asking for Java 16 (Even though I'm building on Java17...), I feel that is going to cause issues in the future.