1. Go to Settings > Mail, Contacts, Calendars.
  2. Tap on your Email Account.
  3. You'll see a message stating there was a problem accessing your account. Please reenter the password for...  Below that message, tap the link Re-enter Password.
  4. Enter your new password and tap Next. Your new password has now been saved.
  5. Tap the Home button and check your email. New messages should appear shortly.