Failed authentication via Roundcube: AUTHENTICATE DIGEST-MD5

Symptoms

In /var/log/plesk-roundcube/errors following record might be found:

IMAP Error: Login failed for [email protected] from xxx.xxx.xxx.xxx (X-Real-IP: xxx.xxx.xxx.xxx). AUTHENTICATE DIGEST-MD5: in /usr/share/psa-roundcube/program/lib/Roundcube/rcube_imap.php on line 193 (POST /?_task=mail&_action=refresh)

Cause

Roundcube cannot use DIGEST-MD5 authorization method.

Resolution

1. Login to the server via SSH.

2. Edit file /usr/share/psa-roundcube/config/config.inc.php file in any text editor;

3. Comment out (un-comment) the CRAM-MD5 authorization type in order to replace DIGEST-MD5 authorization method with default one:

   $config['smtp_auth_type'] = 'CRAM-MD5';
    $config['imap_auth_type'] = 'CRAM-MD5';