The part still isn't CanCollide false? UPDATED!

 local platform = Instance.new("Part")
platform.Parent = game.Workspace.CurrentCamera
platform.CFrame = CFrame.new(12.5, 1.71, 17.43)
platform.Anchored = true
platform.Transparency = .5
platform.Size = Vector3.new(5, 10, 1)
local Players = game:GetService("Players")
 
function onPlayerAdded(player)
    game.StarterGui.LocalScript:Clone().Parent = player
	if  (player:GetRankInGroup(2551575) >= 239) then	
		platform.CanCollide = false
	end
	end

I updated my code, as of 11:26 PM EST, I did what you said (I think) and it still does not work.

:IsInGroup() and :GetRankInGroup take integers, not strings. Get rid of the double quotes on the group ID and it should work.

Some other tips to improve your script:

• :clone() is deprecated in favor of :Clone()

• :GetRankInGroup() returns 0 for a non-member, so the :IsInGroup() call isn't required.

• Your print() call is concatenating an empty string with player.Name. The "".. part can be removed.

• Items in StarterGui are cloned to the player's PlayerGui automatically. Try moving the cloned script to ReplicatedStorage or ServerStorage instead.