i am using a system that was installed using the awesome virtual users with postfix and mysql tutorial (THANKS!). Everything works fine., except for a weird SMTP issue. Testing the system - I am sending mail to another account I have. Mail goes through, but only sometimes. In other times - i get relay denied errors... I am using authentication as instructed, AND I also ticked the encrypted authentication checkbox in my local outlook client. output of telnet to port 25 on the server is: Code: 250-mail.domain.com (this is obviously changed...) 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-STARTTLS 250-AUTH LOGIN PLAIN 250-AUTH=LOGIN PLAIN 250 8BITMIME and mail.log has these lines in it (among others) Code: Jun 11 20:52:12 mail postfix/smtpd: NOQUEUE: reject: RCPT from blablablablabla[xxx.xxx.xxx.xx]: 554 <firstname.lastname@example.org>: Relay access denied; from=<email@example.com> to=<firstname.lastname@example.org> proto=ESMTP helo=<comp1> Any ideas?