Ubisoft has finally released a fix for matchmaking problems that have been affecting North American Rainbow Six Siege players since Operation Grim Sky launched almost two weeks ago. The problem was due to the way certain internet service providers (ISPs) interacted with the game’s servers, exacerbated by optimizations included as part of Grim Sky. Server communication would happen before the connection was acknowledged, causing an unsolvable error and preventing matchmaking from working altogether. Unfortunately, this problem highlighted a much larger issue in how major updates, such as Grim Sky, are handled in Siege. It also would have caused problems with the season pass, as taking away content season pass players had paid for would have caused a potentially even larger uproar than the matchmaking problems caused.

Source: Forbes September 14, 2018 19:41 UTC