problem zimbra LDAP integrate to my app authentication

[manier]

can anyone help with my problem.

we had an IS and we would like to integrate the user login to zimbra internal ldap for authentication.but were having problem i can cannot to the server but i can't authenticate.

our system is developed in php so we use ldap_bind

// using ldap bind
$ldaprdn = 'uid=zimbra,cn=admins,cn=zimbra'; // ldap rdn or dn
$ldappass = '<zimbra_ldap_password>'; // associated password

// connect to ldap server
$ldapconn = ldap_connect("zimbra.mydomain.edu.ph")
or die("Could not connect to LDAP server.");

if ($ldapconn) {

// binding to ldap server
$ldapbind = ldap_bind($ldapconn, $ldaprdn, $ldappass);

// verify binding
if ($ldapbind) {
echo "LDAP bind successful...";
} else {
echo "LDAP bind failed...";
}

}

is the userDN and password is correct?

thanks in advance.