Invite leading to crashed game

So, I’m 80 hours into a co-op game played online with my daughter - on W10 PC - and suddenly we’re not able to play: We boot up, begin the game, I invite her, she accepts, the game crashes at her end. We’ve both got good internet with a small ping, we’ve both validated the game files, restarted, rebooted, left it a week, and still no luck.

Anyone got any ideas?

A post was merged into an existing topic: Crash to Desktop on Joining Co-op (PC)