Multiplayer Bug

[Xynen]

My friends and I have been playing 4 player game for a couple weeks. Today when we attempted to load any save from that campaign 2 of us were not able to load in at all. We all verified files and still couldnt get in.

Is there anything we can do to resume this campaign or must we start over? We had only just gotten to act 2.

[LukanGamer]

make sure your not missing mods or something (though they should be auto downloaded) otherwise idk worst worst case you can look into a skip act1 mod and get like a cheat mod or w/e to remake your characters.

Good luck.

[Raze_Larian]

Are you shutting down all non-essential programs before starting the game, especially anti-virus and anything network related (utility or monitoring programs, etc)?
Have you checked there weren't any changes to firewall settings, etc (possibly due to a program update)?

Can everyone join if the host starts a new game, or loads an old save, that worked before? If so, can the host then load the latest save from your existing playthrough?

Have you tried switching who is hosting? You can test in a new game, or transfer a save from your current playthrough.
Each save is a folder in the '..\Documents\Larian Studios\Divinity Original Sin 2 Definitive Edition\PlayerProfiles\<ProfileName>\Savegames\Story' folder.
In Windows Explorer you can zip a file or folder by right clicking on it/them and selecting 'Send To | Compressed (zipped) Folder' (and similarly in OSX/Finder).

Have you tried joining anyone else?

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 in the lobby. Alternately, create a multiplayer game lobby, exit and try joining.

If you are using any mods, try testing in a new profile without any mods enabled.

Have you tried different ways to join? If the host also has the Steam version, there is the lobby and invite function (and it may help to accept an invitation without the game already running).
There is also Direct Connection, with a Server ID (which the host can get in the Connectivity Menu after starting a new game or loading a save) or IP address. In the latter case, it can help if the host sets up port forwarding in their router to connect to the PC (ports 23253-23262 and 23243-23252), and then the clients should be able to connect to the external IP address.
LAN may be an option, but if you are not on the same local network, it would require VPN software, such as Hamachi or Tunngle.
If you use Discord, that may also be an option.

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 '..\SteamApps\common\Divinity Original Sin 2\DefEd\bin\EoCApp.exe' program file (doesn't matter if the first instance is started through Steam or the executable), select Join Online Game in the Campaign section, switch to the LAN tab, rather than Online, and try joining.