[Dovecot] imposible authenticate dovecot, but authtest and testsaslauthd can

Hi all, Im new and have a problem,

With authtest, i have Authentication

[root@dc9f8f585 ~]# authtest esimon@example.tld Authentication succeeded.

 Authenticated: esimon@example.tld  (uid 501, gid 501)
Home Directory: /home/vmail/domains/
       Maildir: (none)
         Quota: (none)

Encrypted Password: (none) Cleartext Password: (none) Options: (none)

With testsaslauthd, i have Authentication

[root@dc9f8f585 ~]# testsaslauthd -u esimon@example.tld -p edu+123* 0: OK "Success."

But wen try with dovecot, the logs say

Sep 21 13:51:31 dc9f8f585 dovecot-auth: ldap(esimon@example.tld): No password in reply Sep 21 13:51:31 dc9f8f585 imap-login: Aborted login [::ffff:127.0.0.1] Sep 21 13:51:31 dc9f8f585 dovecot-auth: Login process 7 disconnected Sep 21 13:51:31 dc9f8f585 dovecot-auth: Login process 7 connected Sep 21 13:51:31 dc9f8f585 dovecot-auth: Login process 7 sent handshake: PID 3379

Why dovecot need the Password? there is some way for only authenticate?

i using, [root@dc9f8f585 ~]# rpm -qa dovecot dovecot-0.99.11-2.EL4.1

And the authentication is against Active Directory

Thanks for any help. NewZen.