- Are you using any mods?
No mods used.
- If the host creates a new lobby, can you join then? If so, can the latest save from your current playthrough be loaded?
No, I cannot join his lobby, nor can he join mine. But we can both join another one from the friend group (Steam user).
- If you or the host create a new profile and start a new game (without mods), can the other join?
No, same error appears.
- Did either of the other Steam players try joining you via Direct Connection? If they get the same error, can they join using the Steam lobby or invites?
Both other Steam users can join via Direct Connect to the host. I used to be able to do this as well.
- 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 Cache...' button.
Tried this already (forgot to mention, apologies), did not have an effect.
- Try starting two instances of the game on your system and see if you can join a local co-op game. If the problem is data related, this should work fine (though working wouldn't necessarily mean it is a data problem).
I can join other open lobbies, just as I can join the other two friends' games. Just not the original host - even though we have played several sessions together already.
I have not tried the other two options yet, but will get back to you on this thread shortly with our findings. Thanks so far
