Hi there,
I did had the same issue and performing steps below did resolved my issue.
Make a backup copy of of the roundcube config file
Code:
mv /usr/local/cpanel/base/3rdparty/roundcube/config/main.inc.php /usr/local/cpanel/base/3rdparty/roundcube/config/main.inc.php-bak
Open the file with pico,vi (any other editor)
Code:
vi /usr/local/cpanel/base/3rdparty/roundcube/config/main.inc.php
Find for the
$rcmail_config['smtp_pass'] = '%p';
$rcmail_config['smtp_user'] = '%u';
You will find the %u %p in the single quotes. Remove or add them accordingly. If already present remove it. This will look as below
$rcmail_config['smtp_pass'] = '';
$rcmail_config['smtp_user'] = '';
You are done. Try sending email now.. Hops this helps