Sea of Thieves’ appeal lies in very large part to it being extremely easy to try out—Microsoft has put it up on the Game Pass day and date of release, and Game Pass even offers a couple of weeks of free trials to everyone. It is not unreasonable to assume that a large part of the game’s player base, if not most of it, is actually playing via Game Pass.
Which is why it would be an issue if Game Pass players were suddenly unable to access the game, right? But, that is exactly what has happened—the new update for the game seems to have rendered the game inaccessible for some Game Pass players, presumably because the new client messed up some backend license entitlement or something. I don’t know, I’m not a tech person.
The good news is that Microsoft and Rare are already aware of the issue, and they are looking into it, promising to resolve it as soon as possible. Hopefully that’s not too far off.