@Sandeep R It seems to be an SSL issue can you validate your LDAP, the port 636 is LDAPS and 389 is for LDAP. To enable LDAPS, you must install a certificate that meets the following requirements: The LDAPS certificate is located in the Local Computer's Personal certificate store (programmatically known as the computer's MY certificate store). A private key that matches the certificate is present in the Local Computer's store and is correctly associated with the certificate. The private key must not have strong private key protection enabled. The Enhanced Key Usage extension includes the Server Authentication (1.3.6.1.5.5.7.3.1) object identifier (also known as OID). The Active Directory fully qualified domain name of the domain controller (for example, DC01.DOMAIN.COM) must appear in one of the following places: The Common Name (CN) in the Subject field. DNS entry in the Subject Alternative Name extension. The certificate was issued by a CA that the domain controller and the LDAPS clients trust. Trust is established by configuring the clients and the server to trust the root CA to which the issuing CA chains. You must use the Schannel cryptographic service provider (CSP) to generate the key. Hope that helps ... View more