Some people (namely me) have had problems with Exhibition mode in Killer Instinct. Specifically with regards to playing online against your friends. I would send the invite - my friend and I would both join the party - but he wouldn’t join the game. We tried all kinds of things but nothing worked. Finally after a lengthy chat with Xbox technical support I was provided the solution which I figured I would share with you all in case you’re also experiencing this problem.
Basically if you’re experiencing this problem then you need to forward the following ports on your router:
•Port 88 (UDP)
•Port 3074 (UDP and TCP)
•Port 53 (UDP and TCP)
•Port 80 (TCP)
•Port 500 (UDP)
•3544 (UDP)
•4500 (UDP)
In the advanced settings for network you can find your ip address. Call your ISP’s technical support line and in many cases they will be able to forward the ports for you. Or if not they should be able to walk you through it.
Once you’ve done this then you should be able to host matches without a problem. The friend you’re having the issue with won’t be able to host until they do the same thing however they will be able to join any game you host without issue. Hope this helps some people!