This has been a problem with quite a few people. Happens to me randomly on occasion as well. I've posted a couple of times about it, but the situation tends to be different for everyone.

The Mods will probably just end up telling you to check the knowledge base:
http://support.na.square-enix.com/fa...qtop&c=5&sc=39

I've noticed that tends to be their goto response for these issues, as I've yet to see an answer that involved anything other than them saying, "It's a problem on your end."

This thread from zam might help as well:
http://ffxiv.zam.com/forum.html?foru...5461089&page=1

The problem for me just spontaneously resolved itself. I've heard of it randomly resolving for others as well. Some people have never gotten to the bottom of what the problem is and just ended up quitting. I hear that people with wireless internet connections tend to have more problems as well. Anyway, good luck!