My friend tried to automate the Worm Farm and crashed server so he couldn't even join in anymore. I needed to restore earlier backup to get rid of the hopper so the server doesn't crash loop anymore.

Minecraft ver: 1.16.5
Forge ver: 36.2.8
Aquaculture ver: 2.2.3
Server software: Mohist 1.16.5-839

Crash log: https://pastebin.com/xj7jVvj1

Any Bukkit/Forge hybrid is unsupported, which includes Mohist.
Does not happen on a server with just Forge.

Thanks for the fast answer, I'll test it again with just Forge and then report it to Mohist.