title: Why my client could not establish trust relationship for the SSL/TLS secure channel with authority?
body: <p>When I am trying consuming a Web Service with a URL HTTPS it is causing this error message:</p>
  
  <p><strong>[SecurityNegotiationException: Could not establish trust relationship for the SSL/TLS secure channel with authority.</strong></p>
  
  <p>I have already read a solution to accept this trust between my client program (C#) and the HTTPS address:</p>
  
  <pre><code>System.Net.ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) =&gt; { return true; };
  </code></pre>
  
  <p>So my question is why my client could not establish trust relationship for the SSL/TLS secure channel with authority? Does somebody know? Because it seems that this solution is not safe.</p>