title: Google Play Game Services is Unable to authorise my app in developer console
body: <p>I want to add Google Play Game Services into my game. I've followed each step in adding it into my app up to authorisation. When I click <strong>authorise your app now</strong>, it displays a text with waiting, loading and there after a white window opens with no response.</p>
  <p>I have attached screenshots along with this post. Please let me know my mistakes if any or any possible solutions</p>
  <p><img src="https://i.stack.imgur.com/BWao5.png" alt="Authorise Button" /></p>
  <p><img src="https://i.stack.imgur.com/iXBtD.png" alt="enter image description here" /></p>
  <p>This is the white screen after clicking</p>