title: We can't do account linking using iOS's Google assistant app
body: <p>I want to realize account linking to Google account with Google Home.
  On realizing this, our app's flow of account linking follow to
  <a href="https://stackoverflow.com/questions/50931590/google-home-authorization-code-and-authentication-with-google-account/50932537#50932537">this page</a>.<br></p>
  <p>It page shows this.</p>
  <blockquote>
  <ol start="6">
  <li>...so we send back a message saying they need to visit our website to authorize us to access their Google services. We may require them to switch to a mobile device to do this part and even include a link to the login page.</li>
  </ol>
  </blockquote>
  <p>At this part, we use <a href="https://developers.google.com/assistant/conversational/df-asdk/rich-responses" rel="nofollow noreferrer">GoogleHome's rich response</a> to send authentication link to user's mobile device.<br>
  For example,</p>
  <pre><code>    payload: {
              google: {
                  expectUserResponse: true,
                  richResponse: {
                      items: [
                          {
                              simpleResponse: {
                                  textToSpeech: &quot;textToSpeech&quot;
                              }
                          },
                          {
                              basicCard: {
                                  title: &quot;Title&quot;,
                                  formattedText: &quot;formattedText&quot;,
                                  buttons: [
                                      {
                                          title: &quot;ButtonTitle&quot;,
                                          openUrlAction: {
                                              url: &quot;https://accounts.google.com/o/oauth2/v2/auth?access_type=offline&amp;scope=https//www.googleapis.com/auth/calendar.readonly&amp;response_type=code&amp;client_id=xxx.apps.googleusercontent.com&amp;redirect_uri=https//project.com&quot;
                                          }
                                      }
                                  ],
                              }
                          }
                      ]
                  }
              }
          }
      
  </code></pre>
  <p>We can do account linking using Android OS, but iOS can't do that due to 403 error.
  We've investigated <a href="https://developers.googleblog.com/2016/08/modernizing-oauth-interactions-in-native-apps.html" rel="nofollow noreferrer">the cause</a>, it needs to use a specific browser to see google authentication page.</p>
  <p><strong>How can I do account linking to avoid such problem?<br>
  Or could you tell me another way to do account linking to Google account.</strong></p>
  <p>Please excuse my poor English. Thank you.</p>