Not showing "Player has left the server." when someone leaves?

****I was working on a script to when a player leaves the server it will say the player has left server on the chat. But as soon as I join the server, it says that.

local Players = game:GetService('Players')

function onPlayerRemoved(player)
	game:GetService('StarterGui'):SetCore('ChatMakeSystemMessage',{
	Text = ('Server| '.. player.Name .. ' has left the game.');
	Color = Color3.new(.9,.5,.05);
	Font = Enum.Font.SourceSansBold;
	FontSize = Enum.FontSize.Size18;
	})
end

Players.PlayerRemoving:connect(onPlayerRemoved)

for _,player in pairs(Players:GetPlayers()) do
     onPlayerRemoved(player)
end