title: TFS connection error (TF31001)
body: <p>I have been using a TFS Server for 8 months. It was working well yesterday. Today, I can't connect this server. Please see the connection error below.</p>
  
  <blockquote>
    <p>TF31001: Cannot connect to Team Foundation Server at server-pc. The
    server returned the following error: Please contact your
    administrator. There was an error contacting the server. Technical
    information(for administrator): HTTP code 500: Internal Server Error</p>
  </blockquote>
  
  <p>I checked the TFS server, it is online. And I have restarted the TFS applicaton on IIS. Then I clean all cache of TFS server. Until now, I can't connect the TFS server and it shows the previous message. How can I fix it? Thanks all</p>