I Phone 5

[modeste]

Just had 5 emails with no content and dated 01/01/1970. Unable to delete then, then when reopened they had disappeared. Any ideas? TIA

[EDDIE51]

A message from the past?

[Jomlett]

Turn off threading. Go to Settings > Mail, Contacts, Calendars and turn off “Organize by Thread.” This may prevent the phantom messages from appearing.

[Zacs-Master]

Easily googlable:
http://www.forbes.com/sites/amitchowdhry/2016/03/09/apple-ios-glitch-causes-users-to-see-blank-emails-dated-january-1-1970/#131aeb7d7c87

[Zacs-Master]

Users who have seen the email bug have reported fixing it by closing the email app and performing a hard reset on the iPhone – done by holding down the lock and home button until it resets.