I am playing on a private server with only me on it. Sometimes when I use the crafting terminal I get an error message on the server but the client side it still works. Once, the terminal would not open and spam the server with error messages until I broke it and placed it again. However, just now the server completely crashed when I tried requesting items. This is the first time it fully crashed when giving the error.

debug.log

Hmm, it looks like a mod with the ID justverticalslabs is expecting the crafting inventory to have more than 9 input slots, which fails of course. Can you report this issue to that mod's issue tracker and cross-reference this issue so that I can keep up to date with it? Thanks!!