My Client

local MarketplaceService = game:GetService("MarketplaceService")
local Players = game:GetService("Players")
 
local productID = 995097904
 
local function promptPurchase()
	local player = Players.LocalPlayer
	MarketplaceService:PromptProductPurchase(player, productID)
end

script.Parent.MouseButton1Click:Connect(promptPurchase)

My Server Code

local MarketplaceService = game:GetService("MarketplaceService")
local DataStoreService = game:GetService("DataStoreService")
local Players = game:GetService("Players")
 local purchaseHistoryStore = DataStoreService:GetDataStore("PurchaseHistory")
 local productFunctions = {}

--[[productFunctions[IDHERE] = function(receipt, player)
	
end]]

productFunctions[995097904] = function(receipt, player)
	local stats = player:FindFirstChild("leaderstats")
	local Stage = stats and stats:FindFirstChild("Gold")
	if Stage then
			local humanoid,hrp = player.Character:WaitForChild("Humanoid"), player.Character:WaitForChild("HumanoidRootPart")
			player.leaderstats.Stage.Value = player.leaderstats.Stage.Value + 1
			local part = workspace.ObbyStages:FindFirstChild(Stage.Value)
			hrp.CFrame = part.CFrame + Vector3.new(0,1,0)
	end
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

I get the error: Error occurred while processing a product purchase (I'm in test mode in Roblox Studio by the way.)

Anonymous