Dovecot не видит домашний каталог пользователя

Я тестирую свою конфигурацию Dovecot с помощью mutt, но безуспешно. У меня есть пользователь user@example.com, я создал для него домашний каталог с помощью команды maildirmake.dovecot . Но Dovecot не может перейти к домашнему каталогу, даже если я установил разрешения 0777. для этого домашнего каталога.

Журнал ошибок:

imap(user@example.com): Error: chdir(/var/spool/mail/mailboxes/example.com/user) failed: No such file or directory
imap(user@example.com): Debug: Effective uid=5000, gid=5000, home=/var/spool/mail/mailboxes/example.com/user, chroot=/var/tmp/vmail_chroot/
imap(user@example.com): Debug: Home dir not found: /var/spool/mail/mailboxes/example.com/user
imap(user@example.com): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=yes, hidden=no, list=yes, subscriptions=yes location=maildir:/var/spool/mail/mailboxes/example.com/user:LAYOUT=fs
imap(user@example.com): Debug: fs: root=/var/spool/mail/mailboxes/example.com/user, index=, indexpvt=, control=, inbox=/var/spool/mail/mailboxes/example.com/user, alt=
imap(user@example.com): Debug: Namespace : /var/spool/mail/mailboxes/example.com/user doesn't exist yet, using default permissions
imap(user@example.com): Debug: Namespace : Using permissions from /var/spool/mail/mailboxes/example.com/user: mode=0700 gid=default
imap(user@example.com): Error: user user@example.com: Initialization failed: Namespace '': mkdir(/var/spool/mail/mailboxes/example.com/user) failed: Permission denied (euid=5000(<getpwuid() error>) egid=5000(<getgrgid() error>))
imap(user@example.com): Error: Invalid user settings. Refer to server log for more information.

Конфигурация Dovecot:

# 2.2.9: /etc/dovecot/dovecot.conf
# OS: Linux 3.13.0-55-generic x86_64 Ubuntu 14.04.3 LTS ext4
auth_debug = yes
auth_debug_passwords = yes
auth_mechanisms = login digest-md5 cram-md5
auth_verbose = yes
first_valid_gid = 5000
first_valid_uid = 5000
last_valid_gid = 5000
last_valid_uid = 5000
mail_chroot = /var/tmp/vmail_chroot/
mail_debug = yes
mail_location = maildir:/var/spool/mail/mailboxes/%d/%n:LAYOUT=fs
mailbox_list_index = yes
namespace inbox {
  inbox = yes
  location = 
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix = 
  type = private
}
passdb {
  args = scheme=CRYPT username_format=%u /etc/dovecot/users
  driver = passwd-file
}
plugin {
  quota_rule = *:storage=100M
}
protocols = " imap lmtp pop3"
service auth-worker {
  user = $default_internal_user
}
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0666
    user = postfix
  }
}
service imap-login {
  inet_listener imap {
    port = 0
  }
  inet_listener imaps {
    port = 993
    ssl = yes
  }
}
service lmtp {
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0600
    user = postfix
  }
}
service pop3-login {
  inet_listener pop3 {
    port = 0
  }
  inet_listener pop3s {
    port = 995
    ssl = yes
  }
}
ssl_cert = </etc/ssl/certs/x.example.com.pem
ssl_key = </etc/ssl/private/example.com.key
ssl_protocols = !SSLv2 !SSLv3
userdb {
  args = username_format=%u /etc/dovecot/users
  driver = passwd-file
}