https://www.gamespot.com/articles/destiny-2-servers-down-for-maintenance-new-update-/1100-6456433/

Destiny 2 servers have been taken offline for previously scheduled maintenance. They'll remain down for the next few hours as Bungie prepares to roll out the game's next update on PS4, Xbox One, and PC, and it's shaping up to be one of the biggest so far.