I was zoning into The Ruby Sea on Louisoix when the loading screen hung on me for longer than usual and then I was booted out of the game to the initial startup screen. On going to the Character Selection for Louisoix I got this error:

"Unable to obtain character data due to server congestion."

I also heard whilst I was playing that many others were reported to have been kicked out trying to enter duties and couldn't log back in with the congestion error.

The error doesn't seem to affect all servers as I was able to start a new character on Odin so it may just be localized to Louisoix.