mail not delivered because file too large

Hi, I have a problem with mail delivered to several user, when I try to =
send mail I have the following error:

This is the Postfix program at host mail.free-tech.net.
I'm sorry to have to inform you that your message could not be
be delivered to one or more recipients. It's attached below.
[cut]
<pippo@mail.test.net>: cannot access mailbox /var/mail/pippo for user=20
enzo.
error writing message: File too large

... but I have in the my configuration:

[root@mail etc]# postconf -n
[cut]
content_filter =3D smtp-amavis:[127.0.0.1]:10024
cut][
message_size_limit =3D 0
mydestination =3D $myhostname,$mydomain
mydomain =3D free-tech.net
myhostname =3D mail.free-tech.net
mynetworks =3D 10.0.0.0/28, 127.0.0.0/8, 192.168.1.0/28
myorigin =3D $myhostname
newaliases_path =3D /usr/bin/newaliases.postfix
queue_directory =3D /var/spool/postfix
readme_directory =3D /usr/share/doc/postfix-2.0.18/README_FILES
relay_domains =3D $mydestination, $virtual_alias_domains
sample_directory =3D /usr/share/doc/postfix-2.0.18/samples
sendmail_path =3D /usr/sbin/sendmail.postfix
setgid_group =3D postdrop
smtpd_banner =3D $myhostname ESMTP $mail_name ($mail_version)
[cut]
virtual_alias_domains =3D anotherdomain.biz
virtual_alias_maps =3D hash:/etc/postfix/virtual1

...why also with:
message_size_limit =3D 0

... the mail not delivered ? ..moreover if I send mail with =
pippo@test.net I haven't a problem, my problem is only for mail to =
pippo@test.net !!
thanks.

Salvatore.