Infinite Yield On RBLX Servers But Not In Studio?

As with everything i do in some way something goes wrong so i need some help to continue progress in my game.

If i take out the WaitForChild then it gives me an error on line 2 but doesn't happen in studio ( The Error Was Saying That The ModeHandler Didn't Exist )

I Know For A Fact I Have Not Done Any Typos

This is the code i used

Main = game:GetService("Players").LocalPlayer
MP = game:GetService("ServerScriptService"):WaitForChild("ModeHandler")

game.Workspace.NumberPlayers.Changed:connect(function()
    wait(0.5)
    if game.Workspace.NumberPlayers.Value >= 1 then
        Main.PlayerGui.ModePickGUI.RoundShadow.DropShadow.Namez.Text = "?????"
        MP.Disabled = false
        wait(8)
        game:GetService('SoundService').DrumRoll:Play()
        Main.PlayerGui.ModePickGUI.RoundShadow:TweenPosition(UDim2.new(0.314,0,0.343,0))
        wait(2.5)
        Main.PlayerGui.ModePickGUI.RoundShadow.DropShadow.Namez.Text = game:GetService("ServerStorage").Mode.Value
        wait(3)
        Main.PlayerGui.ModePickGUI.RoundShadow:TweenPosition(UDim2.new(0.314,0,-1.343,0))
        script.Disabled = true
    end
end)