Other system use port 636 connect LDAP Server Error

Hi

In ldap server(localhost) , I execute the below command , it ok. # ldapsearch -x -b 'ou=people,dc=mydomain,dc=com' -D "cn=interface,dc=mydomain,dc=com" -H ldaps://192.168.1.10 -W

But in other linux system is not ok, below is the error info: # ldapsearch -x -b 'ou=people,dc=mydomain,dc=com' -D "cn=interface,dc=mydomain,dc=com" -H ldaps://192.168.1.10 -W ldap_bind: Can't contact LDAP server (-1) additional info: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

LDAP Server is Centos 5.8 64 OS, iptables serverice is closed state. What is the cause?

You have any Suggestions? Thanks.

Tian Zhiying