I am the only person on the server able to place the cauldron i checked both maps i run on my cluster and dont have any issues but all other players cannot place the cauldron they can craft it and put it in their hotbar but cannot try to place it down i thought it was a corrupted mod install but it works for me without being an admin but i am also the only person who has bought is there an issue with the free version?
#Gaia Potions Plus
merry cloak
cyan ibex
If they don't own it, they can't use the plus version. If they do own it and still can't place it down, even if you can, it's still likely a corrupted mod issue and they should reinstall the mod client-side and you should reinstall the mod serverside, just to be sure.
Server off > Remove mod > Server on > Server off > Reinstall mod > Server on
If you're running both versions then people who don't own the mod still need to use the free version. The paid verison with the freemium model is only freemium so people who don't own the mod can still join servers with it installed. They shouldn't be able to learn the engram, craft the cauldron, place it down, craft potions inside or use potions crafted in it.