I am having the same issue, with Roundcube 1.1, and cannot seem to find directions anywhere on how to fix it. I am trying to instal Roundcube on a Mavericks server, using SQLite as the database. All goes fine during installation, until the 'Test Config' page. Everything passes, except for the IMAP test. I keep getting the "Temporary authentication failure" message. The IMAP logs say nothing useful, unfortunately.
I have Googled around, but have not found a documented solution. I have found several entries from people who have successfully installed Roundcube on Mavericks server, so I know it's possible. I do not wish to use the topicdesk installer, as it seems to instal and override various settings and configs in the system - like PHP - and I'd rather know exactly what's happening to my server.
Any guidance would be greatly appreciated.