[2023] Multiplayer stops working

Is this all in one particular campaign? Can you start and play a new one MP with these same players?

And, if any mods were involved, please try a new game with no mods.  

You are probably using a different ISP and internet router/modem, would that be right? If so there may be a firewall issue here now.

If you have a VPN try connecting to the internet with that before you start the game; does that help?