In recent builds of roundcube, you may find that you can’t send mail using Roundcube. If /var/cpanel/roundcube/log/errors shows the following:


[30-Jan-2009 14:07:11] Invalid response code received from server (421):
[30-Jan-2009 14:07:11] Invalid response code received from server (-1):
[30-Jan-2009 14:07:34 -0800] SMTP Error: SMTP error: Authentication failure: STARTTLS failed (Code: ) in /usr/local/cpanel/base/3rdparty/roundcube/program/steps/mail/func.inc on line 1248 (POST /3rdparty/roundcube/index.php?_task=mail&_action=send)
[30-Jan-2009 14:10:29] STARTTLS failed ():


Then there is an issue with the most recent Net-SMTP PHP module. To resolve this, edit the following file:


/usr/local/cpanel/base/3rdparty/roundcube/config/main.inc.php

and change

// SMTP username (if required) if you use %u as the username RoundCube
// will use the current username for login
$rcmail_config['smtp_user'] = '%u';

to this:


// SMTP username (if required) if you use %u as the username RoundCube
// will use the current username for login
$rcmail_config['smtp_user'] = '';