Infinite yield possible on.. Error ????

i kept getting this error everytime i run the game.. so this is the error (Infinite yield possible on 'Players.Marrise101.PlayerGui:WaitForChild("WalkSpeedGui"))

and this is the script

local player = game.Players.LocalPlayer
local plrgui = player.PlayerGui
local screengui = plrgui:WaitForChild("WalkSpeedGui")
local frame = screengui:WaitForChild("Frame")
local textbox = frame:WaitForChild("TextBox")

local hum = player.Character.Humanoid
game.Players.PlayerAdded:Connect(function(plr)
	game.Players.CharacterAdded:Connect(function(char)
	if char.Humanoid.WalkSpeed == 0 then
		char.Humanoid = 8
	end
	end)
	
	
	
	end)

textbox.Changed:Connect(function()
	hum.WalkSpeed = textbox.Text
end)