In order for us to see what you did wrong, we need to see your code. However, a solution to this is just checking if there isn’t already a cloned gui before cloning another one.
TeleportPart1.Touched:Connect(function(hit)
if not player.PlayerGui:FindFirstChild("ClonedGUI") then
script.ClonedGUI:Clone().Parent = player.PlayerGui
end
end)
Just checks if there isn’t already a ClonedGUI inside the PlayerGui before cloning and parenting another one.