Running Outlook 2003 on XP service pack 2

Sometimes I send an email and it goes to the outbox but immediately the font
in the outbox changes from italics to regular. I can sometimes move it to
the draft folder and resend and it goes correctly, other times it gets stuck
again.

When I do a send/ recieve, it never attempts to send the mail and just
ignores that it's in the outbox.

I've tried restarting Outlook, putting it into offline mode and then back to
online and also rebooting the PC to no avail. Mail sent after the mail in
question gets hung up go through with not problem.

There seems to be no rhyme or reason to this problem.

Any ideas?

KB