@Zephai (Kveldulf) Can you build the vanilla stuff? And structures from other mods? Since the other players of the server don't have this problem, it seems to be your game file / settings.
One idea is that your istalled game file is corrupted, steam has the option to check the files. But thats a long shot and can probably take a while.

Yeah, I reinstalled the files.. its kinda weird. Eventually after a few hours I could place the cage mod items fine. I heard a few others had a similar issue I did before but with a variety of mods. We are playing on Primitive +. My issue last seemed resolved and perhaps its a bug that comes and goes. I could however place vanilla structures and others from mods along with structures +. I assume if this happens to anyone that it eventually works itself out as I just quit for a few hours of playing with the cage mod.. and I might have logged off and back on a few hours later when I tried again and it was working fine. I have yet to try it today for a follow up. So hopefully going forward its fine. I do get an issue building upside down on a boat only. Its from a mod tho.. so I have yet to look into that issue. Just a bunch of weird things hit me all in one day and I started to look into things.

All the issues seem to have halted on a new day of gaming. So weird how ARK works when it comes to bugs. I do not believe there was a fault with your mod at all. :) You have done one hell of a job!!