Teleport Button GUI isn't working? [SOLVED] [closed]

I've tried using a Local and Server script to make a Teleport button appear when you touch the part. All I get in the output is > 14:33:56 -- TeleportButton is not a valid member of ScreenGui> .

local button = game.Workspace.OtherworldDoor

function onTouch(part)
    game.StarterGui.ScreenGui.TeleportButton.Visible = true
end

button.Touched:connect(onTouch)

EDIT: I found out that moving the code into the GUI's local script makes it work