Like a lot of Massively Multiplayer Online Games that are based in Japan, the games were taken offline due to the aftermath of the crisis in Japan regarding the earthquake and tsunami, as well as the nuclear crisis that has gripped the nation.
The games were ultimately taken offline, as well as a bunch of other online titles with servers in Japan, alongside downloadable content and other retail releases which saw delays (Like Marvel vs Capcom 3’s Jill and Shuma Gorrath) or cancellations (Disaster Report 4 on PS3) following the quake.
The exact reason for the shutting down of the two Final Fantasy online juggernauts was due to power output, and Square Enix’s compliance with energy conservation that is being enforced by the government of Japan to help the country recover, save money and conserve power in the wake of the ongoing crisis. The Play Online service as a whole was also suspended and will be reinstated on March 25th as well. As it makes up 11.6% of Square Enix’s total energy consumption in the Tokyo area.
As a result of the shutting down of the games, players will not be billed for the month of April.
Here is the awesome intro for Final Fantasy XIV.