If you are trying to find how to fix iOS 9.2.1 iPhone empty email from January 1 1970 bug then you should be acknowledge with the next information. This is not the first time when January 1, 1970 bug hit Apple devices owners. Last month, the company acknowledged a bug which caused iOS 9 iPhones and iPads to brick themselves if their date was changed to January, 1970. And now according to lots of users reports another bug, though less harmful, has popped up that also has to do with the same date.
The affected by ghost email from January 1 1970 bug users says that their devices shows that they have one (or few) new email(s) from January 1, 1970 in their inbox folder. The issue only seems to be affecting the stock mail client of iOS, with other third-party apps not being affected by it.
In their reports users indicate that these ghost emails are empty and do not brick their iPhone in anyway. While they can be deleted without any issues, it seems to be reappearing after sometime for some people. Most of the iPhone owners affected by this bug were in a different timezone than the default timezone set on their iOS 9.2.1 iPhone.
So to fix iOS 9.2.1 iPhone empty email from January 1 1970 bug you need to close the mail app and do a hard reset on your affected device.
Fortunately this ghost email from January 1 1970 bug doesn't require any new Apple's firmware release or hard fix process. Those users who has faced with a bug which caused iOS 9 iOS devices brick themselves if their date was changed to January 1, 1970 know that the fix was pushed with iOS 9.3 beta 4 release when the major iOS 9.3 launch is around the corner.