chickenstab

I've recently installed a datapack onto my server, after a lot of fuss and figuring things out, and I've come to discover it all works except for one aspect-- Custom items/object models, which are included as part of the datapack, do not show up. Instead they show as placeholder items. I cannot figure out whats wrong. All folders are in the right place or it wouldn't be working at all in the first place. Does Minehut just not support this sort of thing? The datapack in question is this sandfishing datapack.