How do I can make mTLS using HttpClient to check the certificate on the server

Question

I want to check the SSL/TLS certificate on the server side, so, on the client, when I do

var webHandler = new WebRequestHandler();
var cert = new X509Certificate2(Path, Pass); 
webHandler.ClientCertificates.Add(cert);
webHandler.AuthenticationLevel = AuthenticationLevel.MutualAuthRequired;
var httpClient = new HttpClient(webHandler)

And the posting the request to the GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context), it does not matter if I post the certificate, everytime it works. I want to check the certificate in the GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context) method.

Is it possible?