"Unknown global" warning when trying to pass parameter to FireAllClients()?

So I made 2 scripts for a button, the 1st one is a serverscript and changes the color of a part, and then the serverscript fires a RemoteEvent for all client(it should show GUI to clients).

The only problem is, when I try to pass a parameter to the FireAllClients() function, I get a warning saying "unknown global"

here's the serverscript:

button.ClickDetector.MouseClick:Connect(function()
	
	if not wasItClick then
		
		wasItClick = true
		
		local fire = Instance.new("Fire")
	
		fire.Color = workspace.TweenButton.Part.Color
	
		fire.Parent = workspace.TweenButton.Part

		game.ReplicatedStorage.MakeGUiAppear:FireAllClients(parameter)
		
		wait(2)

		
		wasItClick = false
		
		
	end
	
end)

localscript:

local frame = script.Parent

game.ReplicatedStorage.MakeGUiAppear.OnClientEvent:Connect(function()
	
	
	frame.Visible = true
	
	wait(2)
	
	frame.Visible = false
	
	
	
	
end)

I'm new to scripting, and I've never really done anything involving RemoteEvents before, so if anybody could point out the errors in my code, I would really appreciate it