[2021] 4 men multiplayer CtD crossplay

I have no idea what could possibly cause that very specific problem, I am sorry. Has this always happened with these players, or it was okay up to some point?

Does it matter who is host?

Any mods in use?  

Let me know if changing hosts helps.

And when it crashes do you get OOS errors on the screen or what happens exactly?  

The next patch 1.4.3 has some MP fixes in it:

Steam Multiplayer Open Beta 1.4.3 - Updated for Azure

Update: With the release of Hotfix 1.4.2, the Steam Multiplayer Open Beta is now in version 1.4.3 ===== Hey everyone, Along with the release of the Azure patch we will update the Multiplayer Open Beta today at 10:00 (GMT+2). This new build has... forum.paradoxplaza.com
But that is not available to gamepass players yet, Steam only. Hopefully when that comes out to all platforms it will help you!  

If that patch doesn't help and you get a repeatable crash, then it ought to be fixable, yes - IF it's a game problem! If it is an issue with those particular players (eg a long ping time) then it gets much trickier.  

It is still a game crash rather than out of sync errors or something else?

It still affected the same players in the same was as you described above?

This was in a new campaign, not continuing an old one?  

Then I think there is something wrong with those players' setups in some way. Are they on the same ISP or internet router/modem, something like that?

I see you have Stellaris, can you test with these players in that game too? Player 1 will need to opt into the crossplay branch for that game in the Steam Betas tab for that game.  

Ronimjan said: I have Stellaris, but sadly Player 4 doesn't (as far as I know).

This still only happens when BOTH player 2 and 4 are in the game, not just one of them?

What about players 1 and 3, are either or both of them necessary for this problem to occur?  

They could try deleting the whole Documents/Paradox Interactive/CK3/ folder (except any valued save games) I guess.

If that doesn't help I can only assume this is something about their setup doing this. Quite what I am not sure!

If they use Windows Defender as their firewall, ck3.exe needs to be allowed through it in both the Public and Private domains. Similarly if they have firewalls in their internet routet/modems.  

I don't know then, I'm running out of ideas here. Do these players have other machines at their locations they can use as a test?

Or even i guess at other locations?