Hi Afroz,
Please refer below KBA regarding the same issue
1245218 - How to connect the LDAP plugin to Active Directory
https://service.sap.com/sap/support/notes/1245218
1965433 Setting up AD SSO when CMS is on Unix or Linux in BI4.1 ***BEST PRACTICE***MASTER KBA***
https://service.sap.com/sap/support/notes/1965433
1636349 How To setup Active Directory Single Sign On when BOE CMS is on Unix or Linux for BI4
https://service.sap.com/sap/support/notes/1636349
1253052 LDAP Attributes Explained
https://service.sap.com/sap/support/notes/1253052
1259855 - Troubleshooting LDAP SSL within BOE
https://service.sap.com/sap/support/notes/1259855
Hope this will help!!!
Thanks,
Daya