Mouse is no longer active?

I have a crosshair Gui that follows the mouse when the tool is equipped. But when I unequip it, the output says:

This mouse is no longer active

tool.Equipped:connect(function(mouse)

		print("Tool equipped!")
	
	-- Open Crosshair GUI		
		local gui = tool.CrosshairGUI
		local guiClone = gui:Clone()
		guiClone.Parent = player.PlayerGui
	
	-- Move Crosshair GUI to mouse position		
		local crosshairClone = guiClone:FindFirstChild("Crosshair")
		
		while wait() do
			local mousePosX = mouse.X -- It says this line is the problem
			local mousePosY = mouse.Y --  Same with this one
			crosshairClone.Position = UDim2.new(0, mousePosX - 25 , 0, mousePosY - 25)
			
			-- Hide mouse
			game:GetService("UserInputService").MouseIconEnabled = false
		
	tool.Unequipped:connect(function()
		
		-- Delete Crosshair GUI
		guiClone:Destroy()
		wait()
		
		-- Show mouse
		game:GetService("UserInputService").MouseIconEnabled = true
	end)