Getting exception while passing certificate to web service

See more:

C#

WinForms

SOAP

webservice

SSL

Hi there,

I'm working with window from application that uses the web service. That web service require the client to pass SSL certificate along with its object. But I'm Getting the exception
"cryptographic exception was unhandled Unspecified Error".

Here is my code:

Property24ListingService _service = new Property24ListingService();
            
            // code to tell your application that you have no problems with self-signed SSL certificate
            ServicePointManager.ServerCertificateValidationCallback = delegate(Object obj, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors) 
            {
                return(true); 
            };

                webRef1.CredentialsHeader header = new webRef1.CredentialsHeader();
                header.EMail = email;
                header.Password = pwd;

                _service.CredentialsHeaderValue = header;
              //  _service.ClientCertificates.Add(X509Certificate.CreateFromCertFile(cerPath));
                X509Certificate cer = new X509Certificate(X509Certificate.CreateFromCertFile(cerPath));
                _service.ClientCertificates.Add(cer);

                MessageBox.Show(_service.EchoAuthenticated("hi"));

                var agent = _service.FetchAgent(94);
                MessageBox.Show(agent.ToString());

I'm getting the exception on line where i'm creating the "X509Certificate" object.

Any help would be great!