Developer prompt wont work?

Im trying to make it where when you buy the developer product you gain 5 walk speed but i cant find the problem here. please help if you can

local MarketplaceService = game:GetService("MarketplaceService")
local buyButton = game.StarterGui.ScreenGui.fiveWalkspeed
local productId = 63904167
local Ployer = LocalPlayer.Humanoid
 
buyButton.MouseButton1Click:connect(function()
	MarketplaceService:PromptProductPurchase(player, productId)
	walkspeed = walkspeed + 5
end)

local Ployer

That's kind of a big deal

PromptProductPurchase(player