[Freedombox-discuss] Cannot connect to internal imap server from Roundcube.

[A. F. Cano]

I have set up dovecot on an internal machine. Debian stable up to date.
It works fine when accessed like this from mutt:

mutt -f imaps://<IP address of internal machine>/<mailbox>

>From both the machine where the imap server is and from another machine
in the internal network, after the usual SSL certificate warning.  Mutt
prompts for the username and password.

However, from Roundcube on the FreedomBox it fails:

In the login page of roundcube I enter the user name, the passowrd and in
the field of the server address: imaps://<IP address of the imap server>

and I get "Connection to storage server failed."

In /var/log/roundcube/errors.log I see this:

[02-Aug-2022 16:03:47 -0400]: <d1babvua> IMAP Error: Login failed for <user name>  against 192.168.200.<IP of imap server> from 192.168.200.<IP of FreedomBox>. Could not connect to ssl://192.168.200.<IP of imap server>:993: Unknown reason in /usr/share/roundcube/program/lib/Roundcube/rcube_imap.php on line 200 (POST /roundcube/?_task=login&_action=login)

Is this something I need to tweak in the imap server? What is roundcube
expecting that it might not be getting?  Any ideas as to how to narrow this
down?  What specific tests might I do to find out exactly what the problem is?

Thanks.

Augustine