Hello Roundcube Users

I have an installation of Roundcube 1.1.5 (Version 1.2 is not yet working for me due to plugin dependencies). I noticed that mail cannot be sent using SMTP auth if the MTA (Postfix 2.10.2) has smtpd_delay_reject disabled: http://www.postfix.org/postconf.5.html#smtpd_delay_reject

Postfix' default setting is to have smtpd_delay_reject turned on. Changing nothing else but enabling smtpd_delay_reject Roundcube works flawlessly. But due to specific needs on this server I would like to leave smtpd_delay_reject disabled and have Roundcube cooperate with this setting.

This is Roundcube's error message from my logs: roundcube: <vqg1ssqm> SMTP Error: Connection failed: Invalid response code received from server in /var/www/html/cmail/program/lib/Roundcube/rcube.php on line 1712 (POST /cmail/?_task=mail&_unlock=loading1468917789039&_lang=en_GB&_framed=1?_task=mail&_action=send) roundcube: ERROR: Invalid response code received from server (554)

And this is what Postfix says: postfix/smtpd[28420]: connect from unknown[x.x.x.x] postfix/smtpd[28420]: NOQUEUE: reject: CONNECT from unknown[x.x.x.x]: 554 5.7.1 <unknown[x.x.x.x]>: Client host rejected: Access denied; proto=SMTP postfix/smtpd[28420]: lost connection after CONNECT from unknown[x.x.x.x] postfix/smtpd[28420]: disconnect from unknown[x.x.x.x]

Here's a config snippet of Roundcube's SMTP settings: $config['smtp_server'] = 'tls://smtphost'; $config['smtp_port'] = 587; $config['smtp_user'] = '%u'; $config['smtp_pass'] = '%p';

Is there anything I can do on Roundcube config side? A magic Postfix trick? Thank you for any input!

Best regards lukn