Also, trying to access a "certain" forum will leave me with a message that says "Cannot log on because that service account has been canceled."
Yes, I had this problem. When you log into the final fantasy account management and go into your accounts do you have one for ffxiv that was cancelled? I did and when I reactivated it, my code worked. The one that is cancelled wont say legacy, dont let that confuse you, just reactivate it.