Local Script won't change WalkSpeed?

I have no idea why this is happening but I made it so they can't walk (and jump) when they join (on the server) but when they press the start button they can move again (on the client).

Here are the scripts:

Server Script:

game.Players.PlayerAdded:Connect(function(plr)
	
	local character = plr.Character or plr.CharacterAdded:Wait()
	
	character.Humanoid.WalkSpeed = 0
	character.Humanoid.JumpPower = 0
	
	local leaderstats = Instance.new("Folder")
	leaderstats.Parent = plr
	leaderstats.Name = "leaderstats"
	
	local Wins = Instance.new("IntValue")
	Wins.Parent = leaderstats
	Wins.Name = "Wins"

end)

Local Script:

local localPlayer = game.Players.LocalPlayer
local humanoid = localPlayer.CharacterAdded:Wait():WaitForChild("Humanoid")
script.Parent.MouseButton1Click:Connect(function(plr)
	script.Parent.Parent.Parent.Enabled = false
	if plr == localPlayer then
		humanoid.WalkSpeed = 16
		humanoid.JumpHeight = 7.2
	end
end)

Once again this doesn't make sense to me as I'm pretty sure this should work.

There is a wait in your local script next the wait for child in your humanoid variable

A few things here, you don't need all of that humanoid variable, and you don't need to check if the thing clicking is the localPlayer, it's a local script.

local localPlayer = game.Players.LocalPlayer

script.Parent.MouseButton1Click:Connect(function()
	script.Parent.Parent.Parent.Enabled = false
	localPlayer.Character.Humanoid.WalkSpeed = 16
	localPlayer.Character.Humanoid.JumpHeight = 7.2
end)

It also Happened to me while making a super speed script even I was using local scripts.