Why won't it show the Purchase?

local MarketplaceService = game:GetService("MarketplaceService")
local buyButton = game.Workspace.BuyButton.SurfaceGui.TextButton
local productId = 21248921

buyButton.MouseButton1Click:connect(function()
    MarketplaceService:PromptProductPurchase(game.Players.LocalPlayer)
end)

When you click the GUI it won't show the purchase. (Like stated in the title)

I am sorry for the spam, I need this to be answered. And non of the answers worked, and the thread quickly faded away

Link to the model to help you fix this! http://www.roblox.com/Developer-Product-Donate-button-Broke-Help-item?id=180309958

Make sure to put the script inside the GUI button, if that doesn't work, I'll make you a working script.