I'm an over the road truck driver, and don't necessarily get to log in to play FFXIV at the same place every time I go to play. I was parked for the evening and went to sign in and got the same error.

I was going to post about that, so the original poster would see that it wasn't just him/her having this problem, and found I was not logged in so I did so to find out that Square-Enix had locked my account due to the possibility of fraudulent activity. (I think it's probably because I do sign in at a different location all the time due to my job, may need to call them and see if they can't notate my account of that for potential of future problems?).....yes, before you decide to ask, I do have the security token app installed on my tablet and registerred with Square-Enix.

Anyway, I followed the instructions and reset my password and was able to log in. My suggestion would be to log out of the forums, relog in and see if you get the same message and go through the process.