I have exactly same problem with this game. I bought Divinity with my friends about 3 months ago.
Now we are I think very close to the endgame...
But it is completely not possible to get connection to co-op for the last 2 weekend. We had a plan to have session now, when I am typing this post - but we can't get connection for last 30 minuts.
Obviously PSN Voice Chat and other games works without a problem.
I remember a time when 15 years ago pirating games was a far away less problematic.