Hi there,
I've been reading and I
think I know what the problem is. I just want to confirm it with the community since there isn't a lot of search results for this error.
On the system running Roundcube, when I try to connect to an IMAP server via SSL, I get the message "Connection to Storage Server Failed" and in /var/log/roundcube/errors, I see:
IMAP Error: Login failed for <user> from 1.2.3.4. Could not connect to ssl://<remote_imap_server>:993: Unknown reason in /usr/share/roundcube/program/lib/Roundcube/rcube_imap.php on line 193 (POST /?_task=login?_task=login&_action=login)
On the remote end, I see in /var/log/mail.err:
Feb 3 21:53:24 <remote_imap_server> dovecot: imap-login: Error: SSL: Stacked error: error:14094418:SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca: SSL alert number 48
Here on the forum, I searched for "stacked error" and only got one result:
https://www.roundcubeforum.net/index.php/topic,23669.msg64175.html#msg64175 -it suggests setting the following (and commenting out extended settings for:
$config['imap_conn_options'] = null;
$config['smtp_conn_options'] = null;
I found these to already be set in the defaults.inc.php file, but copied them over to config.inc.php to be sure. This does not solve the issue.
From the reading I have done, it looks like the issue is a self-signed certificate on the IMAP server. With Thunderbird on my PC, I am able to override that, but it looks like I will need to learn how to force Roundcube to override this, or if not possible, I will need to create my own
Certificate Authority and sign the cert on my email server. But if that isn't the problem, I will go nuts because I won't be able to tell if I signed the certs correctly (I am not familiar with the certificate creation tools). Please let me know if that is indeed what I need to do to fix this error. Thanks.
Roundcube version info:
$ apt-cache policy roundcube
roundcube:
Installed: 1.2~beta+dfsg.1-0ubuntu1
Candidate: 1.2~beta+dfsg.1-0ubuntu1
Version table:
*** 1.2~beta+dfsg.1-0ubuntu1 500
500 http://mirrors.linode.com/ubuntu xenial/universe amd64 Packages
500 http://mirrors.linode.com/ubuntu xenial/universe i386 Packages
100 /var/lib/dpkg/status