Empty PrivateKey at x509certificate2

I installed the certificate in local store (win7) with a private key. In C # code, I do this:

        X509Certificate2 cert = null;
        var store = new X509Store(storeName, storeLocation);
        store.Open(OpenFlags.ReadOnly);
        try
        {
            var result = store.Certificates.Find(X509FindType.FindByThumbprint, thumbprint, false);
            ServicePointManager.Expect100Continue = true;
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;
            ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
            cert = result.Count > 0 
                ? result[0] 
                : null;
        }
        finally
        {
            store.Close();
        }
        return cert;

      

        
        
        
      

    

In the cert variable , I have my certificate. BUT something is wrong: HasPrivateKey is true, but PrivateKey does not have any object. And if I post it with a REST request in the C # code of my web application, I have errors:

AcquireCredentialsHandle() failed with error 0X8009030D.
The request was aborted: Could not create SSL/TLS secure channel.

      

        
        
        
      

    

All rights are granted for the certificate in the store. Help with this, what's wrong?

Certutil result in Russian (I hide confidential information with "***"):

certutil -store my "cf 35 63 34 14 30 a0 32 ca 4a 58 b9 7a 7a ab 18 a4 47 7d a4"
================  0 ================
 : 100030
: ******************************
 NotBefore: 07.07.2015 5:00
 NotAfter: 24.12.2023 4:59
: ********************************
  
:
 (sha1): cf 35 63 34 14 30 a0 32 ca 4a 58 b9 7a 7a ab 18 a4 47 7d a4
    = 94c3b04b44d51674a1b7de89c10bd7d7_09614f03-cc81-44e6-a978-81773242876c
    : CertReq-ceda22d5-2893-496a-b8c1-5c9ceaed82f1
   = Microsoft Strong Cryptographic Provider