title: ROPC flow: The request body must contain the following parameter: 'client_assertion' or 'client_secret'
body: <p>I am testing MSAL and ROPC flow. When I run sample <a href="https://github.com/Azure-Samples/ms-identity-python-desktop" rel="nofollow noreferrer">https://github.com/Azure-Samples/ms-identity-python-desktop</a> I get error:</p>
  
  <pre><code>python username_password_sample.py parameters.json
  invalid_client
  AADSTS7000218: The request body must contain the following parameter: 'client_assertion' or 'client_secret'.
  </code></pre>
  
  <p>I was having same problem while following MS documentation and used <em>curl</em>. Please check <a href="https://stackoverflow.com/questions/61200589/how-to-log-on-to-user-mailbox-from-service-using-oauth-and-ms-graph-api/61202110?noredirect=1#comment108305759_61202110">my other question</a> where SO community helped me to solve problem. After adding application registration secret to curl request, I got valid token and I was able to fetch mails.<br>
  What is confusing me is fact that <strong>secret</strong> is not present in <em>parameters.json</em> file.</p>