warning: SASL: Connect to private/auth failed: Connection refused

# 2.2.13: /etc/dovecot/dovecot.conf
# OS: Linux 3.16.0-4-686-pae i686 Debian 8.4 ext4
auth_debug = yes
auth_debug_passwords = yes
auth_mechanisms = plain login
auth_verbose = yes
auth_verbose_passwords = yes
mail_debug = yes
mail_location = maildir:/var/mail/vhosts/%d/%n
mail_privileged_group = vmail
namespace inbox {
  inbox = yes
  location = 
  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    auto = subscribe
    special_use = \Sent
  }
  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }
  prefix = 
}
passdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
postmaster_address = info@user.com.ua
protocols = imap lmtp
service auth-worker {
  user = vmail
}
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0666
    user = postfix
  }
  unix_listener auth-userdb {
    mode = 0600
    user = vmail
  }
  user = dovecot
}
service imap-login {
  inet_listener imap {
    port = 0
  }
}
service lmtp {
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0600
    user = postfix
  }
}
ssl_cert = </etc/ssl/certs/user.crt
ssl_key = </etc/ssl/private/user.key
userdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
config_directory = /etc/postfix
inet_interfaces = all
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
mydestination = localhost
myhostname = user.com.ua
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 11.11.11.11
myorigin = /etc/mailname
readme_directory = no
recipient_delimiter = +
relayhost =
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = private/auth
smtpd_sasl_type = dovecot
smtpd_tls_auth_only = yes
smtpd_tls_cert_file = /etc/ssl/certs/user.crt
smtpd_tls_key_file = /etc/ssl/private/user.key
smtpd_use_tls = yes
virtual_alias_maps = mysql:/etc/postfix/mysql-virtual-alias-maps.cf
virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
virtual_transport = lmtp:unix:private/dovecot-lmtp

unix_listener auth-master {
    mode = 0660
    user = vmail
    group = vmail
  }

pwcheck_method: saslauthd
mech_list: plain login