This is happening to over a dozen users now. The emails send, but they don't move to Sent Items, they sit in the Outbox. The user can't tell if they sent for sure until / unless they get a reply.
If I turn off Cached Mode the items disappear from the Outbox and if I turn it back on they stay gone. But a day or two later the problem comes back.
At the moment I have the 'trouble' users running in non-cached mode, but I would like to get everyone back to cached. Today another user came to me with this same thing, so it appears to be a growing issue.
Any ideas on where this is coming from and how to fix it?
Software/Hardware used: Exchange 2003, Outlook 2003