Error occoured while proccessing product purchase???

I got code off the roblox developer website and edited it to fit my game but i keep getting the same error "Error occoured while proccessing product purchase" can somebody help?

the code:

local MarketplaceService = game:GetService("MarketplaceService")
local DataStoreService = game:GetService("DataStoreService")
local Players = game:GetService("Players")
 

local purchaseHistoryStore = DataStoreService:GetDataStore("PurchaseHistory")
 

local productFunctions = {}

productFunctions[1002260063] = function(receipt, player)
		local player = game.Players.LocalPlayer
		local gun = game.Workspace.GunStuff.Pistol:Clone()
		gun.Parent = player.Backpack
		return true
end
productFunctions[1002281221] = function(receipt, player)
		local player = game.Players.LocalPlayer
		local gun = game.Workspace.GunStuff.Rifle:Clone()
		gun.Parent = player.Backpack
		return true
end
 

local function processReceipt(receiptInfo)
 
	
	local playerProductKey = receiptInfo.PlayerId .. "_" .. receiptInfo.PurchaseId
	local purchased = false
	local success, errorMessage = pcall(function()
		purchased = purchaseHistoryStore:GetAsync(playerProductKey)
	end)
	
	if success and purchased then
		return Enum.ProductPurchaseDecision.PurchaseGranted
	elseif not success then
		error("Data store error:" .. errorMessage)
	end
 
	
	local player = Players:GetPlayerByUserId(receiptInfo.PlayerId)
	if not player then
		
		return Enum.ProductPurchaseDecision.NotProcessedYet
	end
	
	
	local handler = productFunctions[receiptInfo.ProductId]
 
	
	local success, result = pcall(handler, receiptInfo, player)
	if not success or not result then
		warn("Error occurred while processing a product purchase")
		print("\nProductId:", receiptInfo.ProductId)
		print("\nPlayer:", player)
		return Enum.ProductPurchaseDecision.NotProcessedYet
	end
 
	
	local success, errorMessage = pcall(function()
		purchaseHistoryStore:SetAsync(playerProductKey, true)
	end)
	if not success then
		error("Cannot save purchase data: " .. errorMessage)
	end
 
	
	return Enum.ProductPurchaseDecision.PurchaseGranted
end
 

MarketplaceService.ProcessReceipt = processReceipt