title: 401 When trying to get a token
body: <p>I'm trying to implement authorization with PKCE flow in a ReactJS using <code>@auth0/auth0-react</code> library.</p>
  <p>As the docs show I've wrapped the <code>&lt;App/&gt;</code> component with the Auth0Provider component</p>
  <pre class="lang-js prettyprint-override"><code>&lt;Auth0Provider
  domain={DOMAIN}
  clientId={CLIENT_ID}
  redirectUri={REDIRECT_URI}&gt;
  </code></pre>
  <p>Then I've created a <code>&lt;Button/&gt;</code> component that handles the login using the <code>useAuth0()</code> hook:</p>
  <pre class="lang-js prettyprint-override"><code>const LoginButton = () =&gt; {
   const { loginWithRedirect } = useAuth0();
   return (
    &lt;button onClick={ loginWithRedirect }&gt;Sign-in&lt;/button&gt;
   )
  }
  </code></pre>
  <p>So the problem now is that whenever I try to make the login I successfully obtain the <code>code_verifier</code> and then the library handle the call to the token endpoint, but the endpoint returns me 401 without anything on the response, has anyone ever encountered this problem?</p>