title: Randomly occurring Unable to retrieve document from: '[PII is hidden]'
body: <p>I came along with so many questions and answers but could not understand or find solution as my case is bit different.
  I am using Azure with openIdconnect for Active directory authentication (ASP.Net framework 4.6.1)</p>
  <p>it has been years it was working fine but a day before yesterday this error occurred for only about 1 hour. error was occurring when trying to do AD authentication.</p>
  <p>&quot;</p>
  <pre><code>Exception Message: IDX20803: Unable to obtain configuration from: '[PII is hidden]'.
  Inner Exception: System.IO.IOException: IDX20804: Unable to retrieve document from: '[PII is hidden]'. ---&gt; System.Net.Http.HttpRequestException: Response status code does not indicate success: 400 (Bad Request).
  </code></pre>
  <p><code>StackTrace: System.InvalidOperationException: IDX20803: Unable to obtain configuration from: '[PII is hidden]'. ---&gt; System.IO.IOException: IDX20804: Unable to retrieve document from: '[PII is hidden]'. ---&gt; System.Net.Http.HttpRequestException: Response status code does not indicate success: 400 (Bad Request).</code>&quot;</p>
  <p>during this local authentication and remaining whole application was working fine. After 1 hour this issue was automatically resolved.
  same happened yesterday. issue occurred for 1 hour and resolved automatically.</p>
  <p>Other solution are suggesting to modify IdentityModelEventSource.ShowPII = true;
  But I dont think so it requires code modification.
  Please guide what can be reason that this happens for only short time.
  Note: this is happening on only one server all applications on other servers are working fine</p>