Update: We were able to get in about 30 minutes ago in a two-player sloop, but it took several tries.
The open world multiplayer pirate-'em-up Sea of Thieves launched yesterday, and in the finest tradition of online game releases, it was a mess. Our own hearty band of brigands struggled to get aboard until late last night (although they still managed to put together this handy beginner's guide), and developer Rare acknowledged on Twitter today that a large number of players are also having issues.
The situation is apparently proving tougher to resolve than expected, as Rare has now put a temporary halt to new players joining the game.
In order to resolve the issues players are seeing with the servers, we will be temporarily suspending new players joining the game. We'll get everyone back in and playing as quickly as we can!March 20, 2018
There's no indication as to what's causing the issues or when they might be resolved. Soon, hopefully, but for right now, if you're not already out on the water then you may as well go do something else. I've reached out to Rare for more information, and we'll let you know when the main sail is ready to be raised again.