I had a few issues getting setup, but now the servers connect find during setup, and I can login and see my IMAP folders, but the right pane shows "example.com refused to connect" when I click on any folders and does not show any messages. In that text, "example.com" is the name of my web server. The web server and firewall are fine since I can use the rest of the RC installation.
I'm running nginx, postfix, dovecot. This occurs both directly accessing the web server, as well as through my reverse proxy.
If you think you can assist, please let me know what else you might need. I run other hosts on this same server and they are working fine. I'm running 1.3.9 and downloaded the "complete" package.
My installation and initial testing was in Chrome, but I tried with Firefox as well. Firefox just shows a blank right panel, while Chrome shows the "refused to connect" message.
*update it seems related to the following issue since the Chrome console reports "Refused to display '
https://example.com/skins/larry/watermark.html' in a frame because it set 'X-Frame-Options' to 'deny'."
https://github.com/roundcube/roundcubemail/issues/6057