title: Enrolling Android 5.1 device fails without reason
body: <p>I am trying to enroll a fleet of Android 5.1 devices which did never receive a newer version of Android and are not working with any third party ROM. So we're stuck on 5.1.</p>
  
  <p>As the Google Play Services in the ROM was so old, that I couldn't even install the Android Device Policy DPC, I updated the Play Services in the ROM using an update.zip, wiped the device and then enrolled the device using a NFC tag.</p>
  
  <p>Unfortunately, enrollment is not working, and I'm not even getting an error message. The DPC seems to set itself as the device owner, but no enrollment is taking place - the device does not show up on the API, and upon launching the DPC from the application drawer and clicking on the "Get started"-button, we always are presented with "Your system cannot be managed by this app. Please contact your administrator".</p>
  
  <p>Well, I am the administrator and I have no clue, why this is failing.</p>
  
  <p>Has anyone an idea, what the DPC is looking for before deciding that the device cannot be managed? Or how to get a more meaningful message out of the DPC?</p>