Developer Product script not working?

Hi guys! I made this script a couple of months ago, and it was working fine. I came back to it today and it is not working :( Any ideas? Thanks in advance!

local MarketplaceService = game:GetService("MarketplaceService")
local ds = game:GetService("DataStoreService"):GetDataStore("PurchaseHistory")
local productId = 19750967
MarketplaceService.ProcessReceipt = function(receiptInfo) 

    for i, player in ipairs(game.Players:GetChildren()) do
        if player.userId == receiptInfo.PlayerId then



            if receiptInfo.ProductId == productId then

            game.Workspace.player.PlayerGui.ChoosingMap.Frame.Visible = true
            game.Workspace.ChooseMap.Value = true


            end
        end
    end 

    return Enum.ProductPurchaseDecision.PurchaseGranted     
end