SASL problems

[mailing at scastagnoli.info]

I do apologize but I have a problem I cannot solve.
I type:

sasldblistusers2

and I see that user cyrus exists in sasl2.db, that has 644 permissions.
When I try 

testsaslauthd -u cyrus -p cyrus

I found in /var/log/messages the following:

Dec 14 12:42:19 server imap(pam_unix)[2999]: authentication failure; logname= 
uid=0 euid=0 tty= ruser= rhost=  user=cyrus
Dec 14 12:42:22 server saslauthd[2999]: do_auth         : auth failure: 
[user=cyrus] [service=imap] [realm=] [mech=pam] [reason=PAM auth error]

My /etc/imapd.conf has:

sasl_pwcheck_method: saslauthd
sasl_mech_list: PLAIN

and 

ps -elf | grep sasl 

returns:

1 S root      2997     1  0  85   0 -  1048 interr 12:35 ?        00:00:00 
saslauthd -a pam
1 S root      2998  2997  0  85   0 -  1059 interr 12:35 ?        00:00:00 
saslauthd -a pam
1 S root      2999  2997  0  85   0 -  1059 interr 12:35 ?        00:00:00 
saslauthd -a pam
1 S root      3000  2997  0  85   0 -  1048 schedu 12:35 ?        00:00:00 
saslauthd -a pam
1 S root      3002  2997  0  85   0 -  1048 interr 12:35 ?        00:00:00 
saslauthd -a pam


Please, can anyone help me?

Thank you in advance

Stefano C.