I am trying to make it so when i click a certain part. How do i do it?

when you click the part it's meant to affect the gui / slot

an error shows up when i start a local server but not when in normal studio

script.Parent.MouseClick:Connect(function(plr) 
	
	  slotNumber = slotNumber + 1
       slotName = "slot" .. slotNumber

 slot = plr.Parent.PlayerGui.Inventory.bg:FindFirstChild(slotName)
slott = plr.Parent.PlayerGui.Inventory.bg:FindFirstChild(script.Parent.Parent.itemName.Value) 
sslott()

end)

the error message is : 19:27:44.602 - PlayerGui is not a valid member of Players

Thanks

A PlayerGui is an object of the specific player; you are defining PlayerGui as Players (plr.Parent); try doing plr.PlayerGui instead.