Sorry to bother, when you say set up your UDP Port 4321 do you mean I need to open UDP Port 4321? i tried reading on the link you provided but not sure it's for a mac. The link took to me to network settings and it said not available on Mac OSX & Linux. I also installed windows 10 on my MAC via Bootcamp and I don't get the message regarding People behind a CGNat won't be able to join you so I may just play online via Windows 10 (Bootcamp) even though I hate Windows

. Browsing the web on Windows 10 via Bootcamp is impossible (sites sometimes don't open or take forever to load). Basic sites like amazon sometimes take a few tries to open. Not sure if a Windows Update is causing this or Bootcamp. Of course Microsoft and Apple are no help!
looking at my routers manual under firewall looks like I can Port Foward or Port Trigger. Do I need to do any of these for the UDP Port 4321? Ugh, seems a lil advanced but If I screw something up I can always reset my router to factory default

Someone just asked your game info keeps popping up on my screen when I try to host a game.