[LD] Can't assign plot to Sim

I am trying to use the life and death gravesite feature, and it says to “drag Sims remains or occupied burial casket here to assign plot to that Sim” I have done that multiple times and I still can’t seem to figure out how to make it work. It’s just not assigning that Sim to that gravesite. I’ve tried looking it up on YouTube and Google and nothing seems to be working. Can anyone help?

Edit By Crinrict: Adjusted Title to better reflect the issue