I play with my wife and we are about to escape the fort when we logged on yesterday and I cannot invite her. The GOG overlay will not open and the Invite Players button does nothing.

I have toggled all of the connectivity settings on and off as well as reset gog and the game several times. AM I the only one with this problem?

Same here. Since the last 2GB update overlay is not working! Please fix!

It is a known issue and being worked on: https://www.gog.com/forum/divinity_original_sin_2/changelog/post64

Here the same...after 450 hours coop play it is impossible to invite... when will it be fixed?

The same here. After checking all internet connection and firewall the Invite Players doesn't work.
Please Larian fix it!

Ok so the workaround my wife and I are using is to just open up to all players and have her join my lobby really fast before anyone else does. Then i close the invites and we play. Seems the servers still support coop, its just that all of the ways to "invite" anyone whether thru the in game menu or the GOG overlay are not working. we must use lobbies until they fix it.

@gigakain

Just tried that supposed fix. But my friends game just crashes and freezes his entire PC when trying to join. So doesn't seem like a guaranteed fix.