title: Can't sign in to my app's Sandbox on Xbox One in dev mode
body: <ul>
  <li>My dev account was accepted into the Xbox Live Creators Program.</li>
  <li>I made a UWP app in my Dev Center Dashboard.</li>
  <li>I enabled the Xbox Live service, and got a Sandbox ID.</li>
  <li>I added my dev account and my personal account to the authorized Xbox Live test accounts.  I clicked the "Test" button to publish the changes.</li>
  <li>On my Xbox One in dev mode, I changed the Sandbox to the app's Sandbox ID.  It restarted the Xbox.</li>
  </ul>
  
  <p><strong>When I try to sign in to either my dev account or personal account, I get the following error:</strong></p>
  
  <pre><code>Use an account with access to this sandbox
  
  Either the account or title can't use this sandbox. Change the sandbox in
  Settings &gt; Console &gt; Developer settings, or use a different account.
  </code></pre>
  
  <p>I can't even launch the app unless I'm signed in.  Am I missing any steps?</p>
  
  <p>In the "XDKS.1" Sandbox, I'm able to sign in, deploy and launch the app, etc.  But within the app, I'm unable to sign into Xbox Live, and I'm assuming it's because I'm not in the app's Sandbox.</p>