How do I make MakeChatSystemMessage serverwide using a GUI button?

Okay, so I'm using buttons on an GUI to control chat and make system messages. But other people can't see my messsages I send, but I can. Here's my code:

script.Parent.MouseButton1Click:Connect(function() -- the gui button
	bc = BrickColor.new("Institutional white") -- bc is short for BrickColor
	game.StarterGui:SetCore("ChatMakeSystemMessage", {
		Text = script.Parent.Parent.messageBox.Text; -- The textbox that you type your message you want into
		Font = Enum.Font.GothamBold; -- The font
		Color = bc.Color; -- BrickColor.Color
		FontSize = script.Parent.Parent.sizeBox.Text; -- The size of the font, will remove this soon since it's unneeded
	})
end)