I don't know. According to their Twitter, it's a "possible error". However my subscription isn't a year old (July). I've sent an error report and haven't got a response. Sounds like they are trying to gilt me out of a couple months. Not cool.
"We do apologize for this! Due to an extended outage at Amazon's hosting service (which we use), we are unable to process subscriptions at this time. We will process it as soon as it comes back up!