Here's the link for the maillog:
https://paste.fedoraproject.org/paste/kbH2N9Pc~JPuCqVpE1kszQ
OK. There are a couple of things:
Aug 23 21:47:18 ts130 postfix/smtpd[3750]: warning: hostname localhost does not resolve to address 127.0.0.1 Aug 23 21:47:18 ts130 postfix/smtpd[3750]: connect from unknown[127.0.0.1]
That needs to be fixed. What does the entry for 127.0.0.1 look like in /etc/hosts? Have you also defined ::1 to be localhost in /etc/hosts?
Aug 23 21:47:21 ts130 dovecot: imap-login: Login: user=<tdukes>, method=PLAIN, rip=::1, lip=::1, mpid=3754, secured, session=<9W1yjiR08AAAAAAAAAAAAAAAAAAAAAAB>
So you are connecting over TCPv6 from roundcube to dovecot? Is that what you want?
What is the IMAP hostname in the roundcube configuration?
P.