Whenever I launch the game, I get this crash (https://pastebin.com/0JPvJUDU). It only happens after I build my .jar and put it in my mods folder; everything works fine when I run the mod in IntelliJ.

Here are my main class (https://pastebin.com/j8Pxu2qs) and model class (https://pastebin.com/Gi0j3KF1) if that helps.

 

 

 

Don't use `OnlyIn`. Additionally, section off the client events in a separate class to avoid potential issues with accidental classloading on the server.  Don't register the events to multiple buses using multiple methods as well. All of them are on the mod bus, so only register them with one method to it.

Additionally, this crash report seems to indicate that your mod didn't even load, so there is probably something beforehand to which is not mentioned in the classes provided that is most likely causing it to crash. I would suggest setting up your workspace and production environment on the latest forge version in case you are using two different versions.

Updating my Forge version worked. Thanks for the solution, and I'll try to implement your advice!