I have the same problem. The exact wording of the message is:
You have unsent messages in your outbox. Do you want to send them now?
After that another box (errors) states:
The message could not be sent. The authentication setting might not be
correct for your outgoing e-mail [SMTP] server. For help solving this
problem, go to Help, search for "Troubleshoot Windows Mail", and read the
"I'm having problems sending e-mail" section. If you need help determining
the proper server settings, please contact your e-mail service provider.
Port: 25, Secure(SSL): No, Server Error: 501, Error Number: 0x800CCC79
I cannot get rid of the message because there is no unsent messages in my
outbox, and no drafts waiting to go. There was one email which could not be
delivered (which the above message refers to), but I have deleted that one
from the drafts file. A second email, to the same address, went successfully.
How can I get rid of this 'unsent messages' notification when the email it
refers to no longer exists. It is very annoying as the message comes up
every time I send/receive, every time I log onto messages, and every time I
log off.
Really fuggin annoying.