Outlook difficulties on iPad - instead of "sending", messages disappear completely

Hello, my problem centers around using outlook on my ipad mini. After typing emails on my ipad via outlook (set up through mailboxes), the messages completely disappear when I hit send. Why? There is no record of them in my drafts or sent messages, and the intended recipient never receives the message. This happens at random, which makes it more frustrating to try to pinpoint the problem.