That's what it does. I've never heard of one that pops a gui when connecting. I don't know if that's even possible.
Oh, sorry, i must be remembering it wrong, and also, the way you worded your last post
it just closes just as I spawn
This part is what i mean, since i was thinking the message popped up when a player connected and you said that, i thought i was right about it appearing during the loading screen, because that is before you spawn
So now i must ask you, how does it close when you spawn? Isn't there an OK/Done button that you have to click to close it?