Topic: [SOLVED] SMTP Error: SMTP error(451): Failed to add recipient
I am trying iRedOS and just insatlled the same. Installation was pretty smooth but when I try to send email to others I keep getting below error in maillog.
Jul 8 00:08:35 mx1 roundcube: Invalid response code received from server (451):
Jul 8 00:08:35 mx1 roundcube: [08-Jul-2011 00:08:35 -0400]: SMTP Error: SMTP error: Failed to add recipient 'firstname.lastname@example.org' in /var/www/roundcubemail-0.3.1/program/steps/mail/func.inc on line 1365 (POST /webmail/?_task=mail&_action=send)
Any clue why?