Tried getting a gamepad, printed an error, what's the problem?

This code runs when a gamepad is connected to the game from a client side:

local uis = game:GetService("UserInputService")
uis.GamepadConnected:connect(function()
	print("hello!")
end)

It works, but prints this:

12:57:48.405 - GuiService:AddSelectionParent already has selection group with name RBXBackpackSelection, overwriting selection group.

Anyone know what this is supposed to mean?

Also I'm an issue on this and can't get a player's gamepad when they have a gamepad already connected before joining the game.