Validate OPCUA client application instance certificate|OPC UA Standard|Forum|OPC Foundation

Hi,

I have developed OPC UA SERVER application using CSharp(C#) language.

How to validate OPCUA client application instance certificate in OPC UA Server side in AnonymousIdentityToken policy?

My requirement is,

OPC UA server shall validate an OPC-UA Client application instance Certificate in AnonymousIdentityToken policy.

I have tried below code for validating OPCUA client application instance certificate  in anonymousIdentityToken policy but x509obj object getting null value.

// check for anonymous token.
if (args.NewIdentity is AnonymousIdentityToken || args.NewIdentity == null)
{

// check for x509 application instance certificate
X509IdentityToken x509obj = args.NewIdentity as X509IdentityToken;//x509obj return null value here

}