From PCGamingWiki, the wiki about fixing PC games


Self-hosted servers are used in games which don't have a central server for the distribution of game data but a host is still present. One player (usually with the best connection to most of the other players) is determined as the host and each other user sends and receives data from them. When the host leaves, the game either kicks all players or quickly determines another one which can cause connection problems. Games that use self-hosting usually have a matchmaking system to decide which group of computers connects to what host.