i need a little advice with dovecot master user

[Francesco]

Hello,
As a step to migrate to a newer version of dovecot, i've been asked to
configure a master user for logging in into mailboxes of a dovecot 1.2.

I've followed the instructions from this page:

http://wiki1.dovecot.org/Authentication/MasterUsers

but appearently something is going wrong.

I've turned on the auth verbose and what i get in the log is:

2014-06-30 15:25:03 auth(default): Info:
passdb(administrator,127.0.0.1,master): Master user logging in as
user at domain.tld

but the output from a telnet session says:

Trying 127.0.0.1...
Connected to localhost.localdomain.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE
STARTTLS AUTH=LOGIN AUTH=PLAIN] server ready.
a1 login user at domain.tld*administrator <administrator password>
a1 NO [AUTHORIZATIONFAILED] Authorization failed

what i noticed is that if i type a wrong password i get an
AUTHENTICATIONFAILED, which, to me, sounds different from authorization.

what am i doing wrong?

here is the auth configuration:

____________________________________
auth_master_user_separator=*
auth default {
  mechanisms = login plain

  passdb sql {
    args = /etc/dovecot/dovecot-sql.conf
  }

  passdb passwd-file {
    args = /etc/dovecot/passwd.masterusers
    master = yes
    pass = yes
  }

  userdb sql {
    args = /etc/dovecot/dovecot-sql.conf
  }

  userdb static {
    args = uid=65000 gid=65000 mail=maildir:/var/utenti/ADS/%Lu/Maildir
  }

  passdb pam {
  }

  user = root

  socket listen {
    client {
      path = /var/spool/postfix/private/auth
      mode = 0660
      user = postfix
      group = postfix
    }
  }
}
____________________________________