Authenticationg Cacti Version 0.8.7b on OpenLDAP

I've been looking a method to authenticate Cacti on OpenLDAP, so here's how i do it : 

• go to configuration,settings, authentication 
• authentication method : ldap authentication 
• guest user : no user 
• user template : no user 
• ldap settings, server: address ldap server or fqdn
• port standard : 389
• port ssl : 636
• protocol version : 3
• encryption : none 
• referrals : none 
• mode : no searching 
• DN uid=username,ou=people,dc=sample,dc=com 
• search base : "ou=people,dc=sample,dc=com"
• save 
• you may encounter error after logging in your ldap account : Error: Access Denied, please contact you Cacti Administrator.
• you need to add the user under user management for graph appropriate permission