Earlier today, BioWare took servers down for some minor maintenance. When service was restored around 6:00AM PDT, players immediately started reporting issues. Some players could not access their characters at all, while others could not find quest givers - they were simply missing. Even the guild bank had apparently vanished. Within a couple hours - at around 7:30AM PDT - BioWare took down servers to address these issues.
The team released an update, saying:
During last night's maintenance, some areas of the game were reverted to pre-Game Update 1.2 status. Some areas were 'missing' and characters that were in those areas would be unavailable. We took the live servers offline at approx 9:30AM CDT (Austin time).
Our server and deployment teams are now working to rebuild assets for the live servers, but this is unfortunately not a quick process. We currently estimate that our downtime could be up to eight hours, but that time may be extended.
We encourage you to follow along with updates at http://www.darthhater.com/ where they will continue to update us as this issue gets resolved.