Well, looking a bit, that's fun it doesn't work ????
I don't provide directives for the imap authentication, there are fully provided by roundcube.
What about
ll /opt/roundcube/
I want to see file permissions
what about if you reinstall roundcube
yum reinstall smeserver-roundcube roundcube --enablerepo=stephdl
signal-event post-upgrade ;signal-event reboot