The logs say that the connection is "Anonymous", even though the client log (from k-9 for Android) shows that the client is AUTHing and Zimbra's accepting it; because of this, I can't send email out via port 465; it bounces. (Which interacts critically badly with the noted bug in k-9, but that's peripheral here.)
Issue 3240 - k9mail - Message disappears from drafts folder - K-9 Mail is an advanced email client for Android - Google Project Hosting
Is this a bug; should I hang it? Or am I missing something?