Sorry, I'm new, and couldn't find a past list to look this up.

I am having a problem with SMTP auth, communicating with a QMail server. I know it works through Thunderbird, Outlook and OS X mail. Is this a known issue, or am I missing something. I know this is not very descriptive but:

SMTP Error in /opt/www/roundcubemail/program/steps/mail/sendmail.inc (178): SMTP error: authentication failure