Thanks for the thread guys.
If we are experiencing a larger spread of an issue like this it may be related to an ISP blocking a specific port on their customer's networks. The primary goal right now would be for everyone to make sure that the suggested range of ports have been opened on your guys's routers. We'd like you to take a look at this Knowledge Base article for the Ports which will allow the game to run properly. Once these are forwarded, go ahead and try logging in again. If you are still having an issue, feel free to contact the support center for some technical assistance or even troubleshooting here: http://support.na.square-enix.com/co...php?id=20&la=1
In the meantime, if this hasn't cleared up yet, can you go ahead an list of your Internet Service Providers and your regions to see if this may be related?