I have the same problem. On singleplayer all mods work well together with primitive plus. But on the server I still have some old items and no new items from primitive plus. The old items can be skilled but not crafted.

Some people say that primitive plus is not working with any mods but why does it work on singleplayer? Sounds somehow like ♥♥♥♥♥♥♥♥ to me.

there are a couple servers running prim+ official with mods working. if only i could figure out how they did it