message stuck in Outbox but invisible

[Chris]

I have a user who uses RPC/https even in the office (he doesn't want to
change back and forth). Everything seems to be good but with one problem.
In Word or Excel when he chose File, Send to, Mail Recipient (as attachment)
it opens an Outlook form. After typing in the recipient and click Send, the
form closed normally. If you look at the outbox it has nothing but the email
doesn't show up in Sent items. If you log in OWA it showes him that the sent
emails are in Outbox but all envelopes are open. If you open it and send
again. It won't send. If you access the mailbox using Outlook MAPI (online
mode) from another machine then it showed all sent mails stuck in Outbox,
envelops are closed in italic. If you click send/receive they will be sent.
Also, if the user closed his Outlook (rpc/https) on his machine then all
those stucked invisible emails will be sent out immediately. Looks like it
only happens when sent mail from Word or Excel. No problem if he inserts an
file as attachment.

Any idea how to fix it?

 

[Chris]

I'd like to add one more thing. I said when accessing via Outlook MAPI it
showed stucked emails in Outbox in italic. I just noticed that on the left
of each envelops it has 4-5 "-" from top down. I don't know what the icon
means. But not the same as scheduled email to be delivered at a later time.