Are you shutting down all non-essential programs before starting the game, especially anti-virus and anything network related (utility or monitoring programs, etc)?
If the host creates a new game can you join? If so can the latest save from your current playthrough be loaded?
Have you tried joining anyone else in the group?
Have you tried hosting?
Have you tried hosting/joining an Arena match?
Try going into Arena mode, create an arena, open the Connectivity menu and check the settings, then exit to the main menu and try joining. Alternately, create a multiplayer game lobby, exit and try joining.
If you and the host each create a new profile, can you join a new game without any mods enabled?
Try verifying local files: in the Steam library, right click on the game and select Properties, switch to the Local Files tab and then click on the 'Verify Integrity of Game Files...' button.
With the GOG version, in the (optional) Galaxy client, select Divinity: Original Sin 2 in the left column, then click on the More button, and in the Manage menu select 'Verify / Repair'. In Galaxy 2.0, select the game, then the settings icon at the top right (beside the Play button) and under Manage Installation select 'Verify / Repair'.
Note that after verifying files, if any mods you use require
Norbyte's Script Extender, the dll will need to be replaced again. If you verified files before this started, having Galaxy 'fix' the modified dll would effectively give you a different mod configuration than the host, which can cause crashes when joining.
Have you tried different ways to join? Other than Direct Connection, if you and the host use Discord, its invite function may be an option. There is also LAN, but since you are not on the same local network, it would require VPN software, such as Hamachi or Tunngle.
Try resetting your network adapters:
- click Start (or Search in Win 10), type cmd into the search box, right click Command Prompt and select run as administrator.
- type the following command and hit Enter
netsh winsock reset
- when that is done, there should be a message 'Winsock reset completed successfully'
- type exit and hit Enter, then reboot your computer.
For more details, see:
https://iihelp.iinet.net.au/Resetting_Network_Adapter_(Winsock_Reset)
If you can not join other people, either, try starting the game, switch to windowed mode and lower the game resolution (and maybe check the option to mute the sound volume when the game doesn't have focus), start a multiplayer game, hit Esc, open the Connectivity Menu, optionally disable online multiplayer (if it is enabled) and make sure LAN Connections is enabled (or that can be done in the options before starting a new game).
Next, start the game again from the 'EoCApp.exe' program file (doesn't matter if the first instance is started through Galaxy or the executable), select Join Online Game in the Campaign section, switch to the LAN tab, rather than Online, and try joining.
If that doesn't help, please email supportdos2@larian.com with a dxdiag report (WinKey-R, type in dxdiag and hit enter, then when it finishes loading click on the 'Save All Information...' button and save the report somewhere handy).
Also check the '..\SteamApps\common\Divinity Original Sin 2\DefEd\bin' folder for the gold.log and network.log files, and if there are any CrashDump files being created, zip a few together to include.
