- The screenshot shows it's enabled. Is this screenshot of new server or old server?  -------- New server
- Show us the "plugins" setting in Roundcube config file.
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// SQL DATABASE
$config['db_dsnw'] = 'mysqli://roundcube:xxx@127.0.0.1:3306/roundcubemail';

// LOGGING
$config['log_driver'] = 'syslog';
$config['syslog_facility'] = LOG_MAIL;

// IMAP
$config['default_host'] = '127.0.0.1';
$config['default_port'] = 143;
$config['imap_auth_type'] = 'LOGIN';
$config['imap_delimiter'] = '/';
// Required if you're running PHP 5.6 or later
$config['imap_conn_options'] = array(
    'ssl' => array(
        'verify_peer'  => false,
        'verify_peer_name' => false,

// SMTP
$config['smtp_server'] = 'tls://127.0.0.1';
$config['smtp_port'] = 587;
$config['smtp_user'] = '%u';
$config['smtp_pass'] = '%p';
$config['smtp_auth_type'] = 'LOGIN';
// Required if you're running PHP 5.6 or later

$config['smtp_conn_options'] = array(
    'ssl' => array(
        'verify_peer'      => false,
        'verify_peer_name' => false,
    ),
);

// Use user's identity as envelope sender for 'return receipt' responses,
// otherwise it will be rejected by iRedAPD plugin `reject_null_sender`.
$config['mdn_use_from'] = true;

// SYSTEM
$config['force_https'] = true;
$config['login_autocomplete'] = 2;
$config['ip_check'] = true;
$config['des_key'] = 'hzlgSqFX9TTNVmhassi7yGaT';
$config['cipher_method'] = 'AES-256-CBC';
$config['useragent'] = 'NAme'; // Hide version number
//$config['username_domain'] = 'xxxxx.xx';
$config['mime_types'] = '/etc/mime.types';

// USER INTERFACE
$config['create_default_folders'] = true;
$config['quota_zero_as_unlimited'] = true;

// USER PREFERENCES
$config['default_charset'] = 'UTF-8';
//$config['addressbook_sort_col'] = 'name';
$config['draft_autosave'] = 60;

$config['default_list_mode'] = 'threads';
$config['autoexpand_threads'] = 2;
$config['check_all_folders'] = true;
$config['default_font_size'] = '12pt';
$config['message_show_email'] = true;
$config['layout'] = 'widescreen';   // three columns
//$config['skip_deleted'] = true;

// PLUGINS
$config['plugins'] = array('managesieve', 'password', 'enigma', 'zipdownload');

// Global LDAP address book.
$config['ldap_public']["global_ldap_abook"] = array(
    'name'              => 'Global LDAP Address Book',
    'hosts'             => array('127.0.0.1'),
    'port'              => 389,
    'use_tls'           => false,
    'ldap_version'      => '3',
    'network_timeout'   => 10,
    'user_specific'     => true,

    // Search mail users under same domain.
    'base_dn'       => 'domainName=%d,o=domains,dc=xxx,dc=xx',
    'bind_dn'       => 'mail=%u@%d,ou=Users,domainName=%d,o=domains,dc=xxx,dc=xx',

    'hidden'        => false,
    'searchonly'    => false,
    'writable'      => false,

    'search_fields' => array('mail', 'cn', 'sn', 'givenName', 'street', 'telephoneNumber', 'mobile', 'stree', 'postalCode'),

    // mapping of contact fields to directory attributes
    'fieldmap' => array(
        'name'          => 'cn',
        'surname'       => 'sn',
        'firstname'     => 'givenName',
        'title'         => 'title',
        'email'         => 'mail:*',
        'phone:work'    => 'telephoneNumber',
        'phone:mobile'  => 'mobile',
        'phone:workfax' => 'facsimileTelephoneNumber',
        'street'        => 'street',
        'zipcode'       => 'postalCode',
        'locality'      => 'l',
        'department'    => 'departmentNumber',
        'notes'         => 'description',
        'photo'         => 'jpegPhoto',
    ),
    'sort'          => 'cn',
    'scope'         => 'sub',
    'filter'        => '(&(enabledService=mail)(enabledService=deliver)(enabledService=displayedInGlobalAddressBook)(|(obje$
    'fuzzy_search'  => true,
    'vlv'           => false,   // Enable Virtual List View to more efficiently fetch paginated data (if server supports it)
    'sizelimit'     => '0',     // Enables you to limit the count of entries fetched. Setting this to 0 means no limit.
    'timelimit'     => '0',     // Sets the number of seconds how long is spend on the search. Setting this to 0 means no l$
    'referrals'     => false,  // Sets the LDAP_OPT_REFERRALS option. Mostly used in multi-domain Active Directory setups

    'group_filters' => array(
        'departments' => array(
            'name'    => 'Mailing Lists',
            'scope'   => 'sub',
            'base_dn' => 'domainName=%d,o=domains,dc=xxx,dc=xx',
            'filter'  => '(&(|(objectclass=mailList)(objectClass=mailAlias))(accountStatus=active)(enabledService=displayed$
            'name_attr' => 'cn',
            'email'     => 'mail',
        ),
    ),
);
$config['autocomplete_addressbooks'] = array('sql', 'global_ldap_abook')

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- Any error in Roundcube log file (it logs to Postfix log file)?---------Can not find. Where to look. var/log ???