title: Backend instance at custom domain
body: <p>I was unable to access my Backend Instance at custom domain. </p>
  
  <p>For example, I have an app and I access the Normal Instance sucessfully at:</p>
  
  <p>http://www.[my_app_id].appspot.com <strong>or</strong> http://[my_app_id].appspot.com</p>
  
  <p>And I have a backend config name=test and I accessed Backend Instance successfully at:</p>
  
  <p>http://test.[my_app_id].appspot.com</p>
  
  <p>In admin interface, the "Instances" link show the instances of Backend and Normal Instance separately. The content show is the same, but is easy to see when a request go to the Backend Instance and when go to Normal Instance. </p>
  
  <hr>
  
  <p>Then I configured the wildcard "test" in Google Apps to access my Backend Instance at a custom URL:</p>
  
  <p>I continue access the Normal Instance sucessfully at:</p>
  
  <p>http://www.[my_domain].com <strong>or</strong> http://[my_domain].com</p>
  
  <p>But request at</p>
  
  <p>http://test.[my_domain].com</p>
  
  <p>redicted to the Normal Instance instead of Backend Instance.</p>
  
  <p>The doc's said it should work but I cann't at this moment and I need uses custom domain because my app is multitenancy.</p>
  
  <p>What I do wrong?</p>