I have two users who are having the same issue. When they try to email from the iPhone (exchange activesync) the email does not go anywhere after pressing the send button. Nothing is in the sent items, nothing in the outbox, it doesn't even attempt to send it. It just disappears. They are able to receive emails just fine.
One of these uses has another issue. Emails she moves in her Outlook's inbox (to other folders or deletes them), do not move in her Inbox on the iPhone. They accumulate there and are marked as unread.
Both users upgraded to iOS 7. I searched for similar problems but didn't find any, I didn't look for very long. Anybody know whats' up?