In oups.com,
wiwchar typed:
Yesterday I created and answered a number of email messages offline.
Before I logged out of Outlook, I checked the Outbox and they were in
there. This morning, I connected to the lan and started up Outlook.
After a couple of minutes, I checked the sent folder. None of the
emails were in there. I then checked the Outbox and they were not in
there either. I contacted one of the would-be recipients of my emails
30 minutes later and she did not receive any from me.

In the past, I have worked offline many times and the emails ended up
in my sent folder the next morning after connecting to the lan.

Any ideas?

What version of Outlook? What kind of mail account? Do you use the same
Windows login/ same Outlook profile when you're in the office, as well as
out?