Desconection when playing 3 in a session, Dying light 1.

There are no issues when playing with two people. But when we play with three (me and 2 friends), one person always gets disconnected (except for the host)—usually the one who has been in the session the longest. Lately, though, I’m the one who almost always gets disconnected, or sometimes I can't even get in. We all have the same NAT type, so I don't know what the problem could be. We’ve tried switching hosts, but the result is the same.