I assume this is probably intentional, but regardless.. you straight up can't use the legacy crafting interface if you go on a multiplayer server that isn't running the mod, meaning Classic Crafting is mandatory for multiplayer as a result.

This is impossible to work on servers without the mod, sorry, as 2 versions of the same screen(Classic Crafting) with different functions, and auto-crafting are impossible without modding the server-side.