alias doesn't work

[Dexter7]

Hi,
i have 2 machines one Debian, second Ubuntu. There is the same postfix configuration on both of them.

root@machine:~#cat /etc/postfix/main.cf
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
append_dot_mydomain = no
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${queue_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${queue_directory}/smtp_scache
postfix-doc package for
myhostname = localhost.localdomain
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination =
relayhost = 192.168.1.2
mynetworks = 127.0.0.0/8
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = loopback-only
root@machine:~#

root@machine:~# cat /etc/aliases
root: it@somedomain.com
root@machine:~#

On both machines it is suposed to send email for root (from cron,...) to email it@somedomain.com on server 192.168.1.2 which is real mail server.
On debian machine, it is working fine, but on ubuntu machine it is not. If i send email directly to it@somedomain.com than it comes, but if i send it just to root, it doesn't.
Do you know what is wrong?
Here are loogs:

root@machine:~# mail root
Cc:
Subject: aaa
.
Null message body; hope that's ok

root@machine:~# tail /var/log/mail.log
Jun 29 15:50:50 machine postfix/smtp[19951]: CAE235F4964: to=<root@machine.>, relay=192.168.1.2[192.168.1.2]:25, delay=1.4, delays=0.13/0.04/0.03/1.2, dsn=2.0.0, status=sent (250 Ok: queued as 01866A4012)
Jun 29 15:50:50 machine postfix/qmgr[13909]: CAE235F4964: removed
root@machine:~#


server:~ # tail /var/log/mail
Jun 29 15:50:50 server postfix/qmgr[6996]: 01866A4012: from=<root@machine.somedomain>, size=528, nrcpt=1 (queue active)
Jun 29 15:50:50 server postfix/smtpd[2856]: disconnect from unknown[192.168.2.20]
Jun 29 15:50:50 server amavis[2221]: (02221-02) ESMTP::10024 /var/spool/amavis/amavis-20070629T154532-02221: <root@machine.somedomain> -> <root@machine.somedomain> Received: SIZE=528 from server.somedomain ([127.0.0.1]) by localhost (server [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 02221-02 for <root@machine.somedomain>; Fri, 29 Jun 2007 15:50:50 +0200 (CEST)
Jun 29 15:50:50 server amavis[2221]: (02221-02) Checking: <root@machine.somedomain> -> <root@machine.somedomain>
Jun 29 15:50:50 server amavis[2221]: (02221-02) WARN: all primary virus scanners failed, considering backups
server:~ #