Why won't code work? Developer Product Prompting

I want it so that when you click an image button, it prompts the Developer product, but it doesn't work. It is in a local script located under startergui.

local MarketplaceService = game:GetService("MarketplaceService")
local Players = game:GetService("Players")
 
local productID = 453120071

local function promptPurchase()
	local player = Players.LocalPlayer
	MarketplaceService:PromptProductPurchase(player, productID)
end

script.Parent.ShopButton.MouseButton1Click:Connect(promptPurchase)