There's a lot of info in this thread (among others): http://forum.square-enix.com/ffxiv/t...k-10k-2k-error

Short version: One of the network providers (that connect between your compy/ISP and the FF servers) is messed up. Unfortunately, there is very little SE can do about it since it's not completely their gear (think of them needing to complain to their ISP to fix their stuff).