[Dovecot] setgid failed - Not owner

[Zilon X]

Hello ALL,

    I got errors on a new installation, maybe I forgot something.
The system is Solaris, Dovecot 1.2.10, Postfix 2.7.0, MySQL 5.1.25.
Can send mail with dovecot imap, but can`t retrieve the messages.
Strange, I can save and retrieve draft messages ok, files are always
with postfix:postfix ownership.
Sorry if this is newbie question, but can`t find a solution.

Syslog info:

Apr 19 10:10:17 server postfix/qmgr[10654]: [ID 197553 mail.info]
B66EF3FEE7: from=<user at domain>, size=547, nrcpt=1 (queue active)
Apr 19 10:10:17 server dovecot: [ID 583609 mail.info] auth(default):
master in: USER      1       user at domain     service=deliver
Apr 19 10:10:17 server dovecot: [ID 583609 mail.info]
auth-worker(default): sql(user at domain): SELECT
'/var/postfix/domains/domain/user' as home,
'maildir:/var/postfix/domains/domain/user' as mail, 12345 AS uid,
12345 AS gid, concat('dirsize:storage=', quota) AS quota FROM mailbox
WHERE username = 'user at domain' AND active = '1'
Apr 19 10:10:17 server dovecot: [ID 583609 mail.info] auth(default):
master out: USER     1       user at domain
home=/var/postfix/domains/domain/user
mail=maildir:/var/postfix/domains/domain/user   uid=12345
gid=12345       quota=dirsize:storage=10240000
Apr 19 10:10:17 server dovecot: [ID 583609 mail.info]
deliver(user at domain): auth input:
home=/var/postfix/domains/domain/user
Apr 19 10:10:17 server dovecot: [ID 583609 mail.info]
deliver(user at domain): auth input:
mail=maildir:/var/postfix/domains/domain/user
Apr 19 10:10:17 server dovecot: [ID 583609 mail.info]
deliver(user at domain): auth input: uid=12345
Apr 19 10:10:17 server dovecot: [ID 583609 mail.info]
deliver(user at domain): auth input: gid=12345
Apr 19 10:10:17 server dovecot: [ID 583609 mail.info]
deliver(user at domain): auth input: quota=dirsize:storage=10240000
>> Apr 19 10:10:17 server dovecot: [ID 583609 mail.crit] deliver(user at domain): Fatal: setgid(12345(postfix)) failed with euid=12346(dovecot), gid=54322(dovecot), egid=54322(dovecot): Not owner
Apr 19 10:10:17 server postfix/pipe[23327]: [ID 197553 mail.info]
B66EF3FEE7: to=<user at domain>, relay=dovecot, delay=582,
delays=582/0.18/0/0.11, dsn=4.3.0, status=deferred (temporary failure)
_____________________________________________________

Configuration at dovecot.conf:

login_dir = /var/postfix/dovecot/run/login
login_chroot = yes
login_user = dovecot
mail_privileged_group = postfix
mail_full_filesystem_access = yes
passdb sql {
args = /var/postfix/dovecot/etc/dovecot-sql.conf
}
userdb sql {
args = /var/postfix/dovecot/etc/dovecot-sql.conf
}
user = nobody
socket listen {
master {
path = /var/postfix/dovecot/run/auth-master
mode = 0660
user = postfix
group = postfix
}
client {
path = /var/postfix/spool/private/auth
mode = 0660
user = postfix
group = postfix
}
}
_____________________________________________________

Configuration at main.cf:

mail_owner = postfix
default_privs = nobody
virtual_transport = dovecot
dovecot_destination_recipient_limit = 1
smtpd_sasl_type = dovecot
_____________________________________________________

Configuration at master.cf:

dovecot unix - n n - - pipe flags=DRhu user=dovecot:dovecot
argv=/var/postfix/dovecot/libexec/dovecot/deliver -d $(recipient)
_____________________________________________________

Entries at passwd:

postfix:x:12345:12345::/dev/null:/bin/false
dovecot:x:12346:54322::/dev/null:/bin/false

Entries at group:

postfix::12345:
postdrop::54321:
dovecot::54322:
_____________________________________________________



Thank you for any help!