Dovecot не дает логиниться

auth_debug = yes
auth_mechanisms = plain login
auth_verbose = yes
default_process_limit = 1000
disable_plaintext_auth = no
listen = *
mail_debug = yes
mail_location = maildir:/var/spool/mail/%u
mail_privileged_group = mail
namespace {
  inbox = yes
  location =
  prefix =
  separator = /
  type = private
}
passdb {
  args = dovecot
  driver = pam
}
plugin {
  mail_log_fields = uid box msgid size from subject flags
  sieve = /var/sieve-scripts/%u.sieve
  sieve_dir = ~/sieve
  sieve_global_dir = /etc/dovecot/sieve/global/
  sieve_global_path = /etc/dovecot/sieve/default.sieve
}
protocols = imap pop3
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0660
    user = postfix
  }
}
service imap {
  process_limit = 1024
}
service stats {
  unix_listener stats-reader {
    group = mail
    mode = 0660
    user = mail
  }
  unix_listener stats-writer {
    group = mail
    mode = 0660
    user = mail
  }
}
ssl_cert = </etc/ssl/smtpd.pem
ssl_key = # hidden, use -P to show it
userdb {
  driver = passwd
}
protocol pop3 {
  mail_plugins = " mail_log notify"
}
protocol lda {
  deliver_log_format = from=%f subj=%s msgid=%m: %$
  mail_plugins = sieve mail_log notify
  postmaster_address = postmaster@xxx.ru
}
protocol imap {
  mail_max_userip_connections = 1000
}
protocol sieve {
  info_log_path = /var/log/dovecot-sieve.log
  log_path = /var/log/dovecot-sieve-errors.log
}

default_process_limit = 100