roundcube question : connexion au serveur de stockage échoué

J'obtiens cette erreur("la connexion au serveur de stockage en échec") des lignes dans roundcube. J'ai tout vérifié, les configurations et la base de données nom d'utilisateur mot de passe, serveur tous les détails sont propres. quelqu'un peut-il me dire ce que pourrait être le problème. Je suis là en donnant l'ensemble du fichier de configuration.

            <?php
$rcmail_config = array();
$rcmail_config['debug_level'] = 9;
$rcmail_config['log_driver'] = 'file';
$rcmail_config['log_date_format'] = 'd-M-Y H:i:s O';
$rcmail_config['syslog_id'] = 'roundcube';
$rcmail_config['syslog_facility'] = LOG_USER;
$rcmail_config['smtp_log'] = true;
$rcmail_config['log_logins'] = false;
$rcmail_config['log_session'] = false;
$rcmail_config['sql_debug'] = false;
$rcmail_config['imap_debug'] = false;
$rcmail_config['ldap_debug'] = false;
$rcmail_config['smtp_debug'] = false;
$rcmail_config['default_port'] = 143;
$rcmail_config['imap_auth_type'] = NULL;
$rcmail_config['imap_delimiter'] = NULL;
$rcmail_config['imap_ns_personal'] = NULL;
$rcmail_config['imap_ns_other'] = NULL;
$rcmail_config['imap_ns_shared'] = NULL;
$rcmail_config['imap_force_caps'] = false;
$rcmail_config['imap_force_lsub'] = false;
$rcmail_config['imap_force_ns'] = false;
$rcmail_config['imap_timeout'] = 0;
$rcmail_config['imap_auth_cid'] = NULL;
$rcmail_config['imap_auth_pw'] = NULL;
$rcmail_config['imap_cache'] = NULL;
$rcmail_config['messages_cache'] = false;
$rcmail_config['smtp_server'] = '';
$rcmail_config['smtp_port'] = 25;
$rcmail_config['smtp_user'] = '%u';
$rcmail_config['smtp_pass'] = '%p';
$rcmail_config['smtp_auth_type'] = '';
$rcmail_config['smtp_auth_cid'] = NULL;
$rcmail_config['smtp_auth_pw'] = NULL;
$rcmail_config['smtp_helo_host'] = '';
$rcmail_config['smtp_timeout'] = 0;
$rcmail_config['enable_installer'] = true;
$rcmail_config['support_url'] = 'http://poolavadi.com/';
$rcmail_config['skin_logo'] = '';
$rcmail_config['auto_create_user'] = true;
$rcmail_config['log_dir'] = 'logs/';
$rcmail_config['temp_dir'] = 'temp/';
$rcmail_config['message_cache_lifetime'] = '10d';
$rcmail_config['force_https'] = false;
$rcmail_config['use_https'] = false;
$rcmail_config['login_autocomplete'] = 0;
$rcmail_config['login_lc'] = 0;
$rcmail_config['skin_include_php'] = false;
$rcmail_config['display_version'] = false;
$rcmail_config['session_lifetime'] = 10;
$rcmail_config['session_domain'] = '';
$rcmail_config['session_name'] = NULL;
$rcmail_config['session_storage'] = 'db';
$rcmail_config['memcache_hosts'] = NULL; 
$rcmail_config['ip_check'] = true;
$rcmail_config['referer_check'] = false;
$rcmail_config['x_frame_options'] = 'sameorigin';
$rcmail_config['des_key'] = 'nSfL_Rz6tc5NRMqKpw7d&A9=';
$rcmail_config['username_domain'] = 'poolavadi.com';
$rcmail_config['mail_domain'] = '';
$rcmail_config['password_charset'] = 'ISO-8859-1';
$rcmail_config['sendmail_delay'] = 0;
$rcmail_config['max_recipients'] = 0; 
$rcmail_config['max_group_members'] = 0; 
$rcmail_config['useragent'] = 'Roundcube Webmail/RCMAIL_VERSION';
$rcmail_config['product_name'] = 'பூளவாடி மின்னஞ்சல்';
$rcmail_config['include_host_config'] = false;
$rcmail_config['generic_message_footer'] = '';
$rcmail_config['generic_message_footer_html'] = '';
$rcmail_config['http_received_header'] = false;
$rcmail_config['http_received_header_encrypt'] = false;
$rcmail_config['mail_header_delimiter'] = NULL;
$rcmail_config['line_length'] = 72;
$rcmail_config['send_format_flowed'] = true;
$rcmail_config['dont_override'] = array();
$rcmail_config['identities_level'] = 0;
$rcmail_config['client_mimetypes'] = NULL;  # null == default
$rcmail_config['mime_magic'] = NULL;
$rcmail_config['im_identify_path'] = NULL;
$rcmail_config['im_convert_path'] = NULL;
$rcmail_config['contact_photo_size'] = 160;
$rcmail_config['email_dns_check'] = false;
$rcmail_config['plugins'] = array();
$rcmail_config['message_sort_col'] = '';
$rcmail_config['message_sort_order'] = 'DESC';
$rcmail_config['list_cols'] = array('subject', 'status', 'fromto', 'date', 'size', 'flag', 'attachment');
$rcmail_config['language'] = 'en_us';
$rcmail_config['date_format'] = 'Y-m-d';
$rcmail_config['date_formats'] = array('Y-m-d', 'd-m-Y', 'Y/m/d', 'm/d/Y', 'd/m/Y', 'd.m.Y', 'j.n.Y');
$rcmail_config['time_format'] = 'H:i';
$rcmail_config['time_formats'] = array('G:i', 'H:i', 'g:i a', 'h:i A');
$rcmail_config['date_short'] = 'D H:i';
$rcmail_config['date_long'] = 'Y-m-d H:i';
$rcmail_config['drafts_mbox'] = 'Drafts';
$rcmail_config['junk_mbox'] = 'Junk';
$rcmail_config['sent_mbox'] = 'Sent';
$rcmail_config['trash_mbox'] = 'Trash';
$rcmail_config['default_folders'] = array('INBOX', 'Drafts', 'Sent', 'Junk', 'Trash');
$rcmail_config['create_default_folders'] = false;
$rcmail_config['protect_default_folders'] = true;
$rcmail_config['quota_zero_as_unlimited'] = false;
$rcmail_config['enable_spellcheck'] = true;
$rcmail_config['spellcheck_dictionary'] = false;
$rcmail_config['spellcheck_engine'] = 'pspell';
$rcmail_config['spellcheck_uri'] = '';
$rcmail_config['spellcheck_languages'] = NULL;
$rcmail_config['spellcheck_ignore_caps'] = false;
$rcmail_config['spellcheck_ignore_nums'] = false;
$rcmail_config['spellcheck_ignore_syms'] = false;
$rcmail_config['recipients_separator'] = ',';
$rcmail_config['max_pagesize'] = 200;
$rcmail_config['min_keep_alive'] = 60;
$rcmail_config['upload_progress'] = false;
$rcmail_config['undo_timeout'] = 0;
$rcmail_config['address_book_type'] = 'sql';
$rcmail_config['ldap_public'] = array();
$rcmail_config['autocomplete_addressbooks'] = array('sql');
$rcmail_config['autocomplete_min_length'] = 1;
$rcmail_config['autocomplete_threads'] = 0;
$rcmail_config['autocomplete_max'] = 15;
$rcmail_config['address_template'] = '{street}<br/>{locality} {zipcode}<br/>{country} {region}';
$rcmail_config['addressbook_search_mode'] = 0;
$rcmail_config['default_charset'] = 'ISO-8859-1';
$rcmail_config['skin'] = 'larry';
$rcmail_config['mail_pagesize'] = 50;
$rcmail_config['addressbook_pagesize'] = 50;
$rcmail_config['addressbook_sort_col'] = 'surname';
$rcmail_config['addressbook_name_listing'] = 0;
$rcmail_config['timezone'] = 'auto';
$rcmail_config['prefer_html'] = true;
$rcmail_config['show_images'] = 0;
$rcmail_config['htmleditor'] = 0;
$rcmail_config['prettydate'] = true;
$rcmail_config['draft_autosave'] = 300;
$rcmail_config['preview_pane'] = false;
$rcmail_config['preview_pane_mark_read'] = 0;
$rcmail_config['logout_purge'] = false;
$rcmail_config['logout_expunge'] = false;
$rcmail_config['inline_images'] = true;
$rcmail_config['mime_param_folding'] = 0;
$rcmail_config['skip_deleted'] = false;
$rcmail_config['read_when_deleted'] = true;
$rcmail_config['flag_for_deletion'] = false;
$rcmail_config['keep_alive'] = 60;
$rcmail_config['check_all_folders'] = false;
$rcmail_config['display_next'] = false;
$rcmail_config['autoexpand_threads'] = 0;
$rcmail_config['top_posting'] = false;
$rcmail_config['strip_existing_sig'] = true;
$rcmail_config['show_sig'] = 1;
$rcmail_config['sig_above'] = false;
$rcmail_config['force_7bit'] = false;
$rcmail_config['search_mods'] = NULL;  
$rcmail_config['addressbook_search_mods'] = NULL;  
$rcmail_config['delete_always'] = false;
$rcmail_config['delete_junk'] = false;
$rcmail_config['mdn_requests'] = 0;
$rcmail_config['mdn_default'] = 0;
$rcmail_config['dsn_default'] = 0;
$rcmail_config['reply_same_folder'] = false;
$rcmail_config['forward_attachment'] = false;
$rcmail_config['default_addressbook'] = NULL;
$rcmail_config['spellcheck_before_send'] = false;
$rcmail_config['autocomplete_single'] = false;
$rcmail_config['default_font'] = '';