My friend and I have tried every possible solution mash up with the lobbies, the quick play, invites, and so on- and NOTHING will work. We had a small glimmer of hope the fist time- we could actually SEE each other- but the moment we opened the first door, it booted him out and we've been trying every solution for DAYS NOW and the same "ERROR: YOU HAVE LOST YOUR CONNECTION TO THE SESSION" has popped up every time since... And while we are perfectly able to connect to strangers- the game won't let us do a match together even if we search the EXACT SAME TERRITORY on a public match. It's vexing... and with each additional failed match-up it is becoming a personal villain origin story...