[horde] IMP can't connect to mail server.

[Michael Christopher Robinson]

Apr  6 23:09:11 goose dovecot: imap-login: Debug: SSL alert: close
notify [192.168.5.4]

Any thoughts on why horde webmail imp is triggering this?

<?php
// IMAP server
$servers['imap'] = array(
    // ENABLED by default; will connect to IMAP port on local server
    'disabled' => false,
    'name' => 'IMAP on goose',
    'hostspec' => 'mail.robinson-west.com',
    'hordeauth' => true,
    'protocol' => 'imap',
    'port' => 143,
    // Plaintext logins are disabled by default on IMAP servers (see   
    //                                                      RFC 3501
    // [6.2.3]), so TLS is the only guaranteed authentication   
    // available by default.
    'secure' => 'tls',
);

Dovecot is set to ssl=required.  I haven't replaced the default
certificate that is in the CentOS 7 rpm.

I can connect to the server just fine using test.php with secure set 
to yes.  Suggests that this is a configuration error.

I tried downgrading Net_IMAP from 1.1.3 to 1.1.0, didn't help.