GUI Button doesn't define the user?

Hello everyone,

So I have this script for a GUI with a button. When clicked it does the following:

local ID = 4715972 --ID

script.Parent.MouseButton1Click:Connect(function(p)
	if game:GetService("MarketplaceService"):UserOwnsGamePassAsync(p.userId, ID) then
	print("I'm working :D")
	else
		game:GetService("MarketplaceService"):PromptGamePassPurchase(p,ID)	
	end
end)

But then it gives this error: attempt to index local 'p' (a nil value).

It works with a normal button with a clickdetector but not for a GUI with a button. Why so and how do I fix this?

Game-pass (if neccessary idk): https://www.roblox.com/game-pass/4715972/

Thanks in advance! ~snewo12