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 and I can receive emails.

Any help would be greatly appreciated.

Sounds like you might be using a different email provider than your ISP and
trying to use your ISP's server to send mail. For instance--You cannot send
Gmail or other email through your ISP's servers without special settings to
verify your credentials. If that's not the problem, you should ask your ISP
for help and to verify your settings. Test messages must appear in your Inbox
in a successful test.

"Ron J." wrote:

> 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 and I can receive emails.
>
> Any help would be greatly appreciated.