Connection issue

[ilykamml]

When attempting to connect with a friend via Steam, after a period of time, the friend may disconnect from the game with a message indicating that the Steam 2P2 session has failed. Alternatively, the player may not be able to join the session, receiving a message indicating they have been kicked from the session.
Tried vpn form NL, enabling upnp on hot-spot, disabling firewall and AV.
The connection attempt was both on the local network and not on the local network.
At the same time, I can connect to the servers of non-my friends.