That means a different IP Address was detected trying to login to your account, you just need to reset your password, if you need more help contact SE Support on this link


*EDIT* This link for EU Accounts.
http://support.eu.square-enix.com/co...hp?id=903&la=2

This Link for US Accounts.
http://support.na.square-enix.com/co...hp?id=902&la=1