see if either one of you has a proxy going on. also check both your internet connections and see what kind yours is.. besides the ios. this happened to my friend. He didnt know what to do. he finally reset his ipad to its original self. like when you first buy it(original factory condition i think). he was annoyed from doing this, but some reason made it work. So now he can invite me to games. this might not work for you, but you are welcome to try it.