https://www.gamespot.com/articles/destiny-2-servers-down-for-maintenance-update-back/1100-6456137/

It's a big day for Destiny 2, with the first Faction Rally of Season 2 kicking off. Before that happens, though, a new hotfix is set to arrive, the launch of which coincides with maintenance. Servers for the game are offline as Bungie prepares to launch the new update. Here are the details on how long it will take and when the game will come back online. [Update: Maintenance is now complete, and Destiny 2 servers are back up with the Faction Rally event.]