Erreur auth sur dovecot

Bonjour

J’ai installé postfix et dovecot avec le support mysql.

Quand je test en telnet tout marche bien mais des que j’essais de configurer mon adresse de messagerie dans thunderbird j’ai des erreus de connexions.

j’ai suivi ce tuto : http://www.tutodidacte.com/debian-7-wheezy-installer-un-serveur-mail-postfix

Voici les logs

doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:26: add auth_ prefix to all settings inside auth {} and remove the auth {} section completely
doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf line 27: Unknown setting: auth_userdb
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:26: add auth_ prefix to all settings inside auth {} and remove the auth {} section completely
doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf line 27: Unknown setting: auth_userdb

Voici mon dovecot.conf

protocols = imap imaps pop3 pop3s
log_timestamp = "%Y-%m-%d %H:%M:%S "

mail_privileged_group = vmail
log_path = /var/log/dovecot

disable_plaintext_auth = no
auth_mechanisms = plain

mail_home = /home/vmail/%d/%u
mail_location = maildir:/home/vmail/%d/%n:INDEX=/home/vmail/%d/%n/indexes

protocol imap {
#ssl_listen = *:993
}

protocol pop3 {
}
protocol managesieve {
}
protocol lda {
  postmaster_address = contact@mondomain.com
  mail_plugin_dir = /usr/lib/dovecot/modules/lda
  auth_socket_path = /var/run/dovecot/auth-master
}
auth default {
        userdb sql {
        args = /etc/dovecot/dovecot-mysql.conf
        }
        passdb sql {
        args = /etc/dovecot/dovecot-mysql.conf
        }
 socket listen {
  master {
  path = /var/run/dovecot/auth-master
  mode = 0600
  user = vmail
 }
  client {
  path = /var/spool/postfix/private/auth
  mode = 0660
  user = postfix
  group = postfix
  }
 }
}
dict {
}
plugin {
}
ssl = yes
ssl_cert = </etc/dovecot/private/dovecot.pem
ssl_key = </etc/dovecot/dovecot.pem

commande postconf -n

postconf -n
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
broken_sasl_auth_clients = no
config_directory = /etc/postfix
inet_interfaces = all
mailbox_command =
mailbox_size_limit = 0
mydestination = mail.hit-fr.net, ns300858.ip-91-121-66.eu, localhost.ip-91-121-66.eu, localhost
mydomain = hit-fr.net
myhostname = mail.hit-fr.net
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
myorigin = hit-fr.net
readme_directory = no
recipient_delimiter = +
relay_domains = mysql:/etc/postfix/mysql_relay_domains.cf
relayhost =
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
smtpd_sasl_auth_enable = no
smtpd_sasl_exceptions_networks = $mynetworks
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
virtual_alias_maps = mysql:/etc/postfix/mysql_virtual_alias_maps.cf
virtual_gid_maps = static:5000
virtual_mailbox_domains = mysql:/etc/postfix/mysql_virtual_mailbox_domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql_virtual_mailbox_maps.cf
virtual_transport = dovecot
virtual_uid_maps = static:5000

merci pour votre aide