I think all the servers are down now, which makes the optimist in me believe they tracked down what was killing duty finder and are fixing that.
It looks to me like they were taken by surprise:
We are currently experiencing technical difficulties wherein players are unable to log into the North American/European data center Worlds on FINAL FANTASY XIV: A Realm Reborn. The issue is being addressed, and new updates will follow as additional information becomes available.
We apologize for any inconvenience this may cause.
[Date & Time]
From Aug. 25, 2013 6:39 a.m. (PDT)
Unable to log into several Worlds.
North American/European Data Center Worlds