The thing is we can start a new multiplayer game by deleting old save files, that is okay. But, cannot load save files in multiplayer, whenever someone joins to the lobby, the host's paradox account logs out immediately. Yes, we have tried VPN and firewall methods nothing worked. I even deleted all files in steam and launched it in paradox launcher but still...
We have spent more time to find a way to play our multiplayer saves than playing it. We gave up trying too and waiting for Paradox to make an announcement.