Star Wars: The Old Republic had planned to kick off Galactic Season 3 with yesterday’s patch, but apparently some unforeseen issue has derailed that plan, forcing BioWare to temporarily take the season offline.
The unexplained issue was discovered during the in-house testing window when update 7.1.1 was being applied. A hotfix to address the problem will go live soon, as will the new season; the game is otherwise still online as of this writing.
There is going to be a short window of downtime while the fix gets applied, so those who are champing at the bit to get started on Galactic Season 3 are advised to keep their eyes on the related forum thread for timing and details.
source: official forums