IMAP Doesn't Work Right On IOS7 IPhones And IPads
Apr 2014, A bug has been discovered in the most recent release of Apples iphone and Ipad operating system IOS 7, where the email client is returning a "server is not responding" error. This is due to the email client staying open in backround of phone or Ipad and locking out the password. There are pages and pages of forums on the internet reporting this issue and it is one apple have yet to address.
Our workaround for this is to force-close the email client and RESTART the phone. You may have to do this more than once for the email client to work.
forceclose apps: http://support.apple.com/kb/ht5137