Good Morning, and thank you for posting on the Final Fantasy XIV Technical Support Forums.

While an i2501 error is not a technical error, we may still be able to assist. An i2501 is a general error on the Mogstation, as such it can be difficult to diagnose. It can be caused by an abnormal connection, a public network (Internet cafe, University connection), the use of a VPN or simply too many rapid attempts. The system will try to filter out anything it finds to be "strange."

Generally, waiting 24 hours between attempts can help alleviate the error. If this does not solve the issue, it may be necessary to contact Customer Support.

The Support Center can be contacted via phone, chat or email support through the Square Enix Support Center website. Please use this link to direct you to the Final Fantasy XIV support website:
http://support.na.square-enix.com/main.php?id=5382&la=1

Please note live service is available Monday through Friday, 9:00 – 18:00, Pacific Time (Excluding holidays).