Turbine let us know about their scheduled maintenance:

All Turbine services will be down on Monday June 23th from 7:00am - 11:00am Eastern (-4 GMT) for maintenance. During this time the game, billing and authentication servers will be offline. In addition, all Turbine forums will be viewable, but players may not be able to log into their accounts.

The news is also in their game launchers, so you'll be reminded Monday morning!