Is this a problem with the location of my script, or the script itself?

This is currently in the ServerScriptService, and the Gui is in the StarterGui. Any thoughts?

game.StarterGui.ResetPlayerGuiOnSpawn = false
old_fog = game.Lighting.FogStart
local MarketplaceService = game:GetService("MarketplaceService")

function getPlayerFromId(id)
	for i,v in pairs(game.Players:GetChildren()) do
		if v.userId == id then
			return v
		end
	end
	return nil
end
 
MarketplaceService.ProcessReceipt = function(receiptInfo)
	local productId = receiptInfo.ProductId
	local playerId = receiptInfo.PlayerId
	local player = getPlayerFromId(playerId)
	local productName 
	
	-- Down below is an example of a Cash boost
	
	-------------------------------------------------------------------
	
	if productId == 35803838 then
		local cashmoney = game.ServerStorage.PlayerMoney:FindFirstChild(player.Name)
			if cashmoney then
				cashmoney.Value = cashmoney.Value + 5000
			end
		-------------------------------------------------------------------
		-------------------------------------------------------------------
	
	if productId == 35803911 then
		local cashmoney = game.ServerStorage.PlayerMoney:FindFirstChild(player.Name)
			if cashmoney then
				cashmoney.Value = cashmoney.Value + 25000
			end
		-------------------------------------------------------------------
				-------------------------------------------------------------------
	
	if productId == 35803887 then
		local cashmoney = game.ServerStorage.PlayerMoney:FindFirstChild(player.Name)
			if cashmoney then
				cashmoney.Value = cashmoney.Value + 100000
			end
		-------------------------------------------------------------------
		-------------------------------------------------------------------
	
	if productId == 35803946 then
		local cashmoney = game.ServerStorage.PlayerMoney:FindFirstChild(player.Name)
			if cashmoney then
				cashmoney.Value = cashmoney.Value + 1000000
			end
		-------------------------------------------------------------------
	
		-- Down below is an example of a Health boost
		
		-------------------------------------------------------------------
	
		elseif productId == 35803808 then
		local cashmoney = game.ServerStorage.MoneyStorage:FindFirstChild(player.Name)
		local char = player.Character
		char.Humanoid.MaxHealth = char.Humanoid.MaxHealth + 25
		wait()
		char.Humanoid.Health = char.Humanoid.MaxHealth
		-------------------------------------------------------------------
	
		-- Down below is an example of a WalkSpeed boost
	
		-------------------------------------------------------------------
		elseif productId == 35803720 then
		local char = player.Character
		if char then
			local human = char:FindFirstChild("Humanoid")
			if human then
				human.WalkSpeed = human.WalkSpeed + 15
			end
		end
		-------------------------------------------------------------------
		
		-- Down below is an example of a gear giver
		
		-------------------------------------------------------------------
		
    	elseif productId == 35803755 then
		game.ServerStorage.SentryTurret:Clone().Parent=player.Backpack
		
		  -- Example if you want to make another gear giver, delete the 2 lines if you dont need it
	
		-------------------------------------------------------------------
	end
	return Enum.ProductPurchaseDecision.PurchaseGranted	
	end