I am not able to send email in Outlook 2003. I get an "undeliverable" message
stating that "Your message did not reach some or all of the intended
recipients" and then "the following recipients could not be reached".

I test the email account (POP) under "email accounts" and the test works
fine and successfully sends a test message. I am also able to send emails to
people whose email accounts are with my ISP.

Any help would be greatly appreciated.