[imp] Cannot login via SSL

[Otto Stolz]

Hello,

I am trying to get an Imp H3 installation working.

test.php and imp/test.php tell me that I have available all the
necessary PHP, and PEAR, modules.

imp.test, section "PHP Mail Server Support Test", connects to my
IMAP server via TSL, ans SSL, and even tells me, how many messages
I have in my mailbox. Hence, I have incorporated one of the successful
configurations in my imp/config/servers.php file.

Yet, the imp login screen says:
> Error connecting to IMAP server. 0 : Error 0.

Same thing with a different IMAP server: Imp can connect via
imap/notls, but not via imap/ssl/novalidate-cert (though imp/test.php
can do so).

- What could be the reason for this discrepancy between Imp-Login and
   imp/test.php?
- How could I proceed to locate the source of this sibylline error
   message?

My environment:
- Horde 3.1.1
- Imp H3 (4.1.1)
- PEAR: I don't know; imp/test says: "Recent PEAR: Yes"
- PHP 4.4.2
- Apache/1.3.34 (Unix) mod_ssl/2.8.25 OpenSSL/0.9.7e PHP/4.4.2
- Solaris: SunOS 5.9

Response from imp/test.php (excerpt):
> The following configurations were successful and may be used in your imp/config/servers.php file:
...
>     Configuration 3
>         'server' => 'popserver.uni-konstanz.de'
>         'protocol' => 'imap/ssl'
>         'port' => '993'

imp/config/servers.php (excerpt):
> $servers['RZ-Cyrus'] = array(
>     'name' => _("Central Mail Service"),
>     'server' => 'popserver.uni-konstanz.de',
>     'hordeauth' => false,
>     'protocol' => 'imap/ssl',
>     'port' => '993',
>     'maildomain' => 'uni-konstanz.de',
>     'smtphost' => 'mailhub.uni-konstanz.de',
>     'smtpport' => 25,
>     'realm' => '',
>     'preferred' => '',
>     'quota' => array(
>         'driver' => 'cyrus',
>         'params' => array()
>     ),
>     'acl' => array(
>         'driver' => 'rfc2086',
>     ),
> );

Likewise with that other server I have mentioned.

Thanks, in advance, for any useful hint.

Best wishes,
   Otto Stolz