Script to disable movement of the player isn't working?

I am trying to disable movement when a gui is open and enable it when the gui is closed, this is what I have but it doesn't work.

game:WaitForChild("Players").PlayerAdded:Connect(function(player)
    game.StarterGui.MapOpenClose.ImageButton.MouseButton1Click:Connect(function()
        player.CharacterAppearanceLoaded:Connect(function(character) 
if game.StarterGui.Map.Frame.Visible == true then 

       character.Humanoid.WalkSpeed = 0 
end
        end)
    end)


game:WaitForChild("Players").PlayerAdded:Connect(function(player)
    game.StarterGui.MapOpenClose.ImageButton.MouseButton1Click:Connect(function()
if game.StarterGui.Map.Frame.Visible == false then 
player.CharacterAppearanceLoaded:Connect(function(character) 
    character.Humanoid.WalkSpeed = 30


end)
end
    end)
end)
end)