Mailbox can't be created

[Paulo Matos]

Hi,

I have setup postfix master.cf to use dovecot-lda to deliver (using -m) 
all messages to PreInbox:
dovecot   unix  -       n       n       -       -       pipe
     flags=DRhu user=vmail:vmail argv=/usr/libexec/dovecot/deliver -f 
${sender} -a ${recipient} -d ${user}@${nexthop} -m PreINBOX

And enabled lda_mailbox_autocreate.

The message I have now it:
Aug 27 10:02:29 lda(): Info: 
msgid=<dae42d0cf57bf4496a3dd53e162f8281 at localhost.localdomain>: save 
failed to open mailbox PreINBOX: Mailbox can't be created
Aug 27 10:02:29 lda(): Info: 
msgid=<dae42d0cf57bf4496a3dd53e162f8281 at localhost.localdomain>: saved 
mail to INBOX

Why wouldn't dovecot itself be able to create mailboxes?

I am using virtual domains and users on a mysql database through postfix 
and mailboxes saved in MailDir format.

Configuration of dovecot is:
# 2.2.18: /etc/dovecot/dovecot.conf
# OS: Linux 4.1.5-x86_64-linode61 x86_64 Fedora release 22 (Twenty Two) ext4
auth_debug = yes
auth_mechanisms = plain login digest-md5 cram-md5
auth_verbose = yes
auth_verbose_passwords = yes
default_internal_user = root
imap_client_workarounds = delay-newmail tb-extra-mailbox-sep
lda_mailbox_autocreate = yes
mail_debug = yes
mail_location = maildir:/home/vmail/%d/%n/Maildir
maildir_very_dirty_syncs = yes
mbox_write_locks = fcntl
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 = INBOX.
   separator = .
   type = private
}
passdb {
   args = /etc/dovecot/dovecot-sql.conf.ext
   driver = sql
}
postmaster_address = pmatos
protocols = imap
quota_full_tempfail = yes
service auth {
   unix_listener /var/spool/postfix/private/auth {
     group = postfix
     mode = 0666
     user = postfix
   }
   unix_listener auth-master {
     mode = 0600
     user = vmail
   }
   user = $default_internal_user
}
ssl = required
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem
userdb {
   args = uid=5000 gid=5000 home=/home/vmail/%d/%n allow_all_users=yes
   driver = static
}
protocol lda {
   auth_socket_path = /var/run/dovecot/auth-master
   deliver_log_format = msgid=%m: %$
   log_path = /home/vmail/dovecot-deliver.log
}
protocol imap {
   mail_max_userip_connections = 100
}

Regards,

-- 
Paulo Matos