Square Enix has announced that for the time being they have halted all sales of the newly released Final Fantasy XIV: A Realm Reborn due to extreme demand overtaking server capacity.
Square Enix posted a statement on the matter last night:
Important Notice About FINAL FANTASY XIV: A Realm Reborn - Due to the overwhelmingly positive response to FINAL FANTASY XIV: A Realm Reborn, we are currently experiencing extremely long wait times for users to be able to log in and play. As a temporary measure, we will halt sales of FINAL FANTASY XIV: A REALM REBORN's digital download products so we can accommodate all of those wishing to play. We are working to expand our server capacity in the coming days.