HttpWebRequest: The request was aborted: Could not create SSL/TLS secure channel
<p>I'm making a asp.net web forms application which offers to pay using paypal. The application is supposed to make use of ssl. When i run my application all goes well until i select my button pay by paypal. When i press this button the following error occurs:</p>

<blockquote>
  <p>The request was aborted: Could not create SSL/TLS secure channel.</p>
  
  <p>Description: An unhandled exception occurred during the execution of
  the current web request. Please review the stack trace for more
  information about the error and where it originated in the code. </p>
  
  <p>Exception Details: System.Net.WebException: The request was aborted:
  Could not create SSL/TLS secure channel.</p>
  
  <p>Source Error: </p>
  
  <p>Line 203: Line 204:        //Retrieve the Response returned from the
  NVP API call to PayPal. Line 205:        HttpWebResponse objResponse =
  (HttpWebResponse)objRequest.GetResponse(); Line 206:        string
  result; Line 207:        using (StreamReader sr = new
  StreamReader(objResponse.GetResponseStream()))</p>
  
  <p>Source File: C:\Users\willem\documents\visual studio
  2015\Projects\WingtipToys\WingtipToys\Logic\PayPalFunctions.cs<br>
  Line: 205</p>
</blockquote>

<p>Below my method in which the error ocurs</p>

<pre><code>public string HttpCall(string NvpRequest)
{
    string url = pEndPointURL;

    string strPost = NvpRequest + "&amp;" + buildCredentialsNVPString();
    strPost = strPost + "&amp;BUTTONSOURCE=" + HttpUtility.UrlEncode(BNCode);

    HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);
    objRequest.Timeout = Timeout;
    objRequest.Method = "POST";
    //objRequest.ContentLength = strPost.Length;

    try
    {
        using (StreamWriter myWriter = new StreamWriter(objRequest.GetRequestStream()))
        {
            myWriter.Write(strPost);
        }
    }
    catch (Exception)
    {
        // No logging for this tutorial.
    }

    //Retrieve the Response returned from the NVP API call to PayPal.
    HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
    string result;
    using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
    {
        result = sr.ReadToEnd();
    }

    return result;
}
</code></pre>