I posted this on another thread...but the original poster of that thread is getting a different error message, so I'll try this one here... I used the postfix with virtual users and mysql tutorial...and I'm using Lenny This is the error I'm getting while trying to send using Outlook I am able to use webmail to send emails...and I am receiving SOME emails from other domains...but if I send an email from my work email address I get the email bounced back to me saying this There is NO ERROR in the mail log. Here is my smtpd.conf file My postfix main.cf This... telnet localhost 25 ehlo localhost returns this... I do have "my server requires authentication" selected in Outlook...and I have no idea why the email from my work address gets bounced back. Any ideas? Thanks.