Turbine let us know that the Account Maintenance site will be down for a while on Monday, and thus access to the game:

The Turbine Account Maintenance site will be brought down for maintenance on Monday, February 2nd from 7:00 AM to 12:00 PM Eastern (-5 GMT). During this time, players will be unable to log into the game or make changes to their accounts. Players already in the game when the site is brought down will be unaffected unless they log out or are disconnected.