This just in:
Trident:
Players with the Turbine Launcher
Currently, the login servers are down, we as of yet do not have an ETA for when the issues will be resolved. We will keep you informed as to when the servers will be back up as we receive the information.
See the original thread for more information.
UPDATE:
Ibn:
The fix passed QA and was quickly installed on the billing servers, which have been brought back online. At this time players should not experience any issues logging in to the game through the Turbine Launcher.
We apologize for this unplanned downtime.