Hello,
We are aware a small number of customers are experiencing issues when trying to set up their subscription for Final Fantasy XIV: A Realm Reborn. Customers affected by these issues are receiving either a 401 or a 601 error code message when attempting to enter their payment information.
For Customers Receiving Error 401
If you are receiving an error 401 message when attempting to enter a new payment method or updating an old one, there is an issue with your financial institution declining the authorization attempt. Unfortunately, Square Enix is not provided with any information as to why the authorization was declined. Please be sure that all billing information is entered correctly on the Square Enix Account. Please be aware that once authorization has been declined, that form of payment method cannot be used for a full twenty-four hours.
If you are unable to resolve the issue with your financial institution, then contact our Support Center for further assistance here. When contacting the Support Center, please note that you will need to verify your account information.
For Customers Receiving Error 601
If you are receiving an error 601 message when attempting to enter a new payment method or updating an old one, the error maybe caused if you are on a private network or on a company network. If possible, we recommend that you try using an outside network to register your payment method to your Square Enix Account. As repeated registration failure can lead to restrictions being placed on your account, we strongly recommend that you contact the Square Enix Support Center for guidance before attempting to register a Credit/Debit card again.
Square Enix Support Center
http://support.na.square-enix.com/main.php?id=5382&la=1