Why cant i add Players to the Table?

Im just getting this error all the time :

Players.Player1.PlayerGui.Menu.Menu.Start Game.Start Game.Click:9: bad argument #1 to 'insert' (table expected, got nil)

here is the script

function EndMenu()
wait()
local frame = script.Parent.Parent.Parent
local play = script.Parent

for i , v in pairs(game.Players:GetPlayers()) do
    wait(0.5)
if v then
    table.insert(_G.gameplayers,v.Name)
    end
frame.Visible = false 
end
end

script.Parent.MouseButton1Down:connect(EndMenu)

I want that if u click the Textbutton you willö be added to the Table _G.gameplayers