Remeshi

I also had issues with Sponge too, turned out my Forge version didn’t match the Sponge API build I was using. Double-check that your mod versions line up correctly. If you're also trying to get visual stuff running smoothly with mods on, I got better performance after switching to minecraft shaders 1.21.7 paired with a lighter resource pack.

I had a similar issue before, and it turned out the plugin version didn’t match the server version. Double-checked compatibility and it started working fine after updating both.