Because Do not respond to the Russian forum, I will duplicate this topic here. Today is Monday and I can not connect to my wife again.

Google Translate:
And so, when we acquired the game with my wife, tried to play a joint game, there was an error: “Error connecting to the game session. Try again later.” He began to google, to google that supposedly these are ports. Hour 4 spent opening already open ports. After some time, nothing is changing with their network connected. It was Sunday. On other weekdays, everything is connected from the first time. Now here again is Sunday and we can not play. Looks like a weekend at yubisoft server load. Why they do not increase the server. I bought two licenses for the sake of playing together, precisely on Sunday people have a weekend, when you can play after a week of work. Please pay attention to this problem.
And it is also not conveniently done, after this error pops up, to make the next attempt to connect, you need to restart the game because the Invite a friend or Join the game menu does not come out.
I also note if you ask for help in the game, then someone left quickly connects.

Original:
https://forums-ru.ubi.com/showthread...B3%D1%80%D0%B5