Outlook: When I send an email message it doesn't leave my outbox

Outlook: When I send an email message it doesn't leave my outbox

I ran into this problem today and was baffled until I found this link:

http://office.microsoft.com/en-ca/outlook-help/when-i-send-an-e-mail-message-it-doesn-t-leave-my-outbox-HA001187988.aspx
The above link says that it describes Outlook 2003, but the information applies to my Outlook 2010.

The symptoms are that in Outlook 2010, when I send a message, it goes to the outbox but is not in italics and does not get sent. 
I can forward that same message and the copy goes just fine.  Also, this is a global problem on several Outlook profiles, not just one.

The culprit turns out to be an Outlook Addin from Apple.  I apparently had installed the application called iCloud on my laptop, and ever since then this problem existed.  

I was able to simply disable this Addin and the problem was resolved.