There are many occurrences when I attempt to log in that I receive this message.
When I see the message I must attempt to log in again. Occassionally it occurs frequently in one sitting, prompting me to refresh or close and open a new page to attempt again.
Sometimes I get logged out while in the game after a few minutes or hours (it varies), though sometimes I can remain logged in for hours on end.
Is this a common occurrence, or am I just 'special'?