cyrus sasl authentication not working

[kyiu]

I'm trying to get the saslauthd to work on my CentOS Linux release 7.3.1611 (Core)
I want to use simple plain text. The ultimate goal is to set up a smtp relay server with postfix using Cyrus SASL authentication

Here is the error:

# testsaslauthd -u xxx@domain.local -p xxxxx
0: NO "authentication failed"

# tail messages
saslauthd[3924]: do_auth : auth failure: [user=xxx@domain.local] [service=imap] [realm=] [mech=pam] [reason=PAM auth error]

Here is my configuration....

# cat /etc/sasl2/smtpd.conf
pwcheck_method: saslauthd
auxprop_plugin: sasldb
# mech_list: PLAIN LOGIN
mech_list: PLAIN LOGIN CRAM-MD5 DIGEST-MD5 NTLM

# cat /etc/sysconfig/saslauthd
SOCKETDIR=/run/saslauthd
MECH=pam
FLAGS=

What's wrong??