Ok... this might be more helpful error message. I went to the Tools->E-mail Accounts->Test Settings window in MS Outlook 2003 and attempt to test my settings. This the error message I get:
Send test e-mail message: The specified server was found, but there was no response from the server. Please verify that the port and SSL information is correct. To access these settings close this dialog, then click More Settings and the Advanced tab.
My STMP is set to port 25. I haven't changed ANY of the settings. It's been working fine for over 6 months until like last week. I can still send with my ISP e-mail address. STMP is set to port 25 for that on too. Thanks.