coop black screen

[L'aventure c'est l'aventure]

I tried most of the tricks described at https://steamcommunity.com/app/1129580/discussions/0/4027970580223563740/#c4027970580223626999

I get an error

How does it work exactly? I am trying to connect within a LAN, with the same public IP.

[L'aventure c'est l'aventure]

error 4-CT (so connectivity issue, I gather)

[L'aventure c'est l'aventure]

windows firewall was set off on both computers, for testing purpose.

[Morri]

Is this when you try to join someone else's game?
What happens when you try to start a new game on Oxbow in "co-op" mode? Do you get an error as well then?

[L'aventure c'est l'aventure]

It happens when I try to join a game that was just started on Oxbow in "co-op" mode.

If I start the game, it starts perfectly fine. But the other player get the black screen when trying to connect.

[L'aventure c'est l'aventure]

Is there any way to know where and how the computer is trying to connect?

Windows firewall was set off on both computer, but they are behind a protected LAN. I have no issues with any other multiplayer game (yersterday BG3 in LAN mode, Portal 2 in internet mode).

Where is the game logging activity so we can found how where it is trying to connect?

[L'aventure c'est l'aventure]

Ok, it is in C:\Users\User_Name\AppData\Local\Medieval_Dynasty\Saved\Logs I'll check if these provides meaningful info.

[Oga]

One that people often miss is that it attempts to connect to Epic Online Services and does all connections using upnp.
If upnp is blocked on either of the sides modem or other firewall device that can cause your black screens.

Something that worked for me a few versions ago, host saved game, everyone closed the game, as soon as the host was in we could join. If one was late(r), he or she would end up on a black screen.

Hope it helps.