How to sell developer products?

So I have this script in my game, when you click a button gui, a prompt should appear and ask if you want to purchase the developer product.

Well, this doesn't work. The prompt does not appear. Any help? It's on a server script. Thanks.

local plr = script.Parent.Parent.Parent.Parent.Parent
local link = game:GetService("MarketplaceService")
deb = 0


script.Parent.MouseButton1Click:connect(function()
    local marketId = 102107544 --ID OF YOUR DEVELOPER PRODUCT  
    link:PromptProductPurchase(plr,marketId)
    link.ProcessReceipt = function(receiptInfo)
        if Enum.ProductPurchaseDecision.PurchaseGranted and receiptInfo.PlayerId == plr.userId then
            if deb == 0 then
                deb = 1
                plr.leaderstats.Candy.Value = plr.leaderstats.Candy.Value + 100
                wait(1)
                deb = 0
            end
        end
    end
end)