why won't my script create a screengui in the players PlayerGui?

I made a script that creates a screengui with a frame in it and then also in the screengui is a textlabel and i'm using game.Players.PlayerAdded:connect(function(plr)

heres my script

game.Players.PlayerAdded:connect(function(plr)
local gui = Instance.new("ScreenGui", plr.PlayerGui)
	gui.Name = "Main"
	wait(1)
	local frame = Instance.new("Frame", gui)
	wait(1)
	local Text = Instance.new("TextLabel", gui)
	Text.Name = "Load"
	wait(1)
while wait(5) do
	plr.PlayerGui.Main.Load.Visible = true
	wait(0.1)
	plr.PlayerGui.Main.Load.Text = "[Loading] 7%"
	wait(0.5)
		plr.PlayerGui.Main.Load.Text = "[Loading] 13%"
	wait(0.3)
		plr.PlayerGui.Main.Load.Text = "[Loading] 20%"
	wait(0.5)
	plr.PlayerGui.Main.Load.Text = "[Loading 27%"
	wait(0.3)
	plr.PlayerGui.Main.Load.Text = "[Loading] 33%"
	wait(0.5)
	plr.PlayerGui.Main.Load.Text = "[Loading] 40%"
	wait(0.3)
		plr.PlayerGui.Main.Load.Text = "[Loading] 47%"
	wait(0.5)
	plr.PlayerGui.Main.Load.Text = "[Loading] 53%"
	wait(0.3)
	plr.PlayerGui.Main.Load.Text = "[Loading] 60%"
	wait(0.5)
		plr.PlayerGui.Main.Load.Text = "[Loading] 67%"
	wait(0.3)
		plr.PlayerGui.Main.Load.Text = "[Loading] 74%"
	wait(0.5)
	plr.PlayerGui.Main.Load.Text = "[Loading] 83%"
	wait(0.3)
		plr.PlayerGui.Main.Load.Text = "[Loading] 95%"
	wait(0.5)
	plr.PlayerGui.Main.Load.Text = "[Loading] 100%"
	wait(0.3)
	plr.PlayerGui.Main.Load.Text = "Loading Complete!"
	wait(0.5)
		plr.PlayerGui.Main.Load.BackgroundTransparency = 0.2
	wait(0.1)
		plr.PlayerGui.Main.Load.BackgroundTransparency = 0.4
	wait(0.1)
		plr.PlayerGui.Main.Load.BackgroundTransparency = 0.6
	wait(0.1)
	plr.PlayerGui.Main.Load.BackgroundTransparency = 0.8
	wait(0.1)
		plr.PlayerGui.Main.Load.BackgroundTransparency = 1
	wait(0.1)
		plr.PlayerGui.Main.Load.Text = ""
	wait(0.1)
	plr.PlayerGui.Main.Load:remove()
	wait(0.1)
	plr.PlayerGui.Main.Frame.Visible = true
end
end)

The answer is simple: PlayerGui hasn't loaded yet. You're better off putting this in a local script, or adding plr:WaitForChild("PlayerGui") after game.Players.PlayerAdded:connect(function(plr)