LDAP login failing with error :
ldap_bind(): Unable to bind to server: Can't contact LDAP server [authentication.php:116 ? CLdapAuthValidator->validate() ? CLdap->checkPass() ? ldap_bind() in /usr/share/zabbix/include/classes/class.cldap.php:112]
LDAP: cannot bind by given Bind DN.
Login name or password is incorrect!

LDAP service manager sends error from log :
Unknown CA
*************
The config I am using
LDAP Host ldaps://services.fnal.gov
Port 636
Base DN dc=services,dc=fnal,dc=gov
Search attribute sAMAccountName
Bind DN*
cn=cd-srv-zabbix,ou=FermiServiceAccounts,dc=services,dc=fnal,dc=gov
Bind Password*
I do have new DigiCertCA.crt and ldap.conf pointing to the correct directory.
telnet services.fnal.gov 636 opens the port also.
I do have php-ldap-5.3.3-27.el6_5.1.x86_64 installed