Also suffering from this issue; been unable to login on my main on Chaos, Louisoix since the game came back up from maintenance about 7 hours ago. World-visiting from the login menu doesn't let me login to the character on a different Chaos world, but data center traveling to Light lets me login to the game and play normally. Alts on different DCs can login normally, but characters I created today on Chaos can't login (tested Sagittarius and Omega).

I'm severely disappointed that there hasn't been an announcement from SE acknowledging the issue, especially as it has been on-going for several hours and it's very disruptive to the gameplay experience.