I am having this issue as well, and it is currently exclusive to Blood Bowl 2 on my Xbox. It is also being heavily reported in the FB group at the moment, as I've seen at least 10 people complaining of it. It seems to sporadically give this message for the first 10 or so minutes of being in the game. Since I am now rebooting, and reloading after every game to improve overall in game stability, and this issue will knock me out of ladder ques every time it appears, it is quite an annoyance. I would say it appeared in the last two weeks, if I were guessing.
I've been having the same for about 2 weeks. Pops up while searching for games and stops the search. Not happened in game as yet. Seems more common to happen straight after watching a game on Cabalvision. Sometimes only happens once sometimes I give up searching as it recurs so much.
No issue on any other games or internet in general.