We will be performing maintenance at the following date and time in order to address login issues being experienced on Worlds hosted on the North American and European datacenter.

During this period, players will be unable to log in to the Worlds listed below.

We apologize for any inconvenience this may cause and thank you for your patience.

[Date & Time]
Aug. 25, 2013 from 9:00 p.m. to 10:30 p.m. (PDT)

According to what's posted on the launcher