title: Could not establish trust relationship for SSL/TLS secure channel -- SOAP
body: <p>I have a simple web service call, generated by a .NET (C#) 2.0 Windows app, via the web service proxy generated by Visual Studio, for a web service also written in C# (2.0). This has worked for several years, and continues to do so at the dozen or so places where it is running.</p>
  <p>A new installation at a new site is running into a problem. When attempting to invoke the web service, it fails with the message saying:</p>
  <blockquote>
  <p>Could not establish a trust relationship for the SSL/TLS secure
  channel</p>
  </blockquote>
  <p>The URL of the web service uses SSL (https://) -- but this has been working for a long time (and continues to do so) from many other locations.</p>
  <p>Where do I look? Could this be a security issue between Windows and .NET that is unique to this install? If so, where do I set up trust relationships? I'm lost!</p>