Emails not sending: "503 valid RCPT command must precede DATA"

[Guest]

I found some info on resolving this at the link below, which suggested
uninstalling AV and disabling firewall and my issue is not resolved. I
cannot send ANY emails. I did a system restart. I have not had any previous
problems like this before. I upgraded to MS Office Pro 2003 3 weeks ago and
am on a Windows 2000 system (latest releases and SP installed). Any
suggestions on the problem?

http://www.microsoft.com/office/com...fice-outlook&lang=en&cr=US&sloc=en-us&m=1&p=1

 

[Guest]

I found some info on resolving this at the link below, which suggested
uninstalling AV and disabling firewall and my issue is not resolved. I
cannot send ANY emails. I did a system restart. I have not had any previous
problems like this before. I upgraded to MS Office Pro 2003 3 weeks ago and
am on a Windows 2000 system (latest releases and SP installed). Any
suggestions on the problem?

http://www.microsoft.com/office/com...office-outlook〈=en&cr=US&sloc=en-us&m=1&p=1

I cleaned out the registry and did another system restart and have
successfully sent and received a bunch of emails. My firewall is engaged,
but I have not re-installed my AV. I will do that next. I'd like to
understand why this problem may have cropped up and how to prevent it again,
so any suggestions would be helpful. Thanks.