Weird physic problem - Clipping

Hi everyone, and thanks for reading this. I googled as much as I could, but I don’t even know what to look for.

So here is the context: I have a system do build… well, buildings, like a classic survival. But now, whenever I walk on any of the building I place, my character wants to clip through them, and I can outright walk through walls!

Another interesting thing, is that it only happens when I play as client (I plan on making the game multiplayer), which was not a problem before. When I don’t play as client, everything is fine, which somehow infuriates me even more.

I probably did a stupid mistake (I hope so at least), but would REALLY like your help. I don’t want to go forward until this sudden bug is solved.

Here is the file to the project for those of you brave enough to help me (Also, if anyone knows a way to share files on reddit without taking so much time downloading it, please tell me). THis bug did not exist litteraly 10 minutes ago, and would like it gone

UPDATE :: I don’t know if this helps, but I loaded an old version of my project, (That I know never had this problem), and now eventhat version does it