title: Google Play Games not log in(don't show pop up)
body: <p>When I open my application, nothing happens (login), so I look for errors in logcat using monitor, and find it says the following: "Could not register one or more required Java classes". See the below errors in logcat:</p>
  
  <pre><code>08-08 15:06:50.971: E/GamesNativeSDK(4247): Could not register one or more required Java classes.
  08-08 15:06:50.975: E/Unity(4247): InvalidOperationException: There was an error creating a GameServices object. Check for log errors from GamesNativeSDK
  08-08 15:06:50.975: E/Unity(4247):   at GooglePlayGames.Native.PInvoke.GameServicesBuilder.Build (GooglePlayGames.Native.PInvoke.PlatformConfiguration configRef) [0x00033] in &lt;d16b8fff80ee43648e71441c5bd39741&gt;:0 
  08-08 15:06:50.975: E/Unity(4247):   at GooglePlayGames.Native.NativeClient.InitializeGameServices () [0x00101] in &lt;d16b8fff80ee43648e71441c5bd39741&gt;:0 
  08-08 15:06:50.975: E/Unity(4247):   at GooglePlayGames.Native.NativeClient.Authenticate (System.Action`2[T1,T2] callback, System.Boolean silent) [0x000ef] in &lt;d16b8fff80ee43648e71441c5bd39741&gt;:0 
  08-08 15:06:50.975: E/Unity(4247):   at GooglePlayGames.PlayGamesPlatform.Authenticate (System.Action`2[T1,T2] callback, System.Boolean silent) [0x00026] in &lt;d16b8fff80ee43648e71441c5bd39741&gt;:0 
  08-08 15:06:50.975: E/Unity(4247):   at GooglePlayGames.PlayGamesPlatform.Authenticate (System.Action`1[T] callback, System.Boolean silent) [0x0000d] in &lt;d16b8fff80ee43648e71441c5bd39741&gt;:0 
  08-08 15:06:50.975: E/Unity(4247):   at GooglePlayGames.PlayGamesPlatform.Authenticate (System.Action`1[T] callback) [0x00000] in &lt;d16b8fff80ee43648e71441c5bd39741&gt;:
  </code></pre>
  
  <p>a had use the Google plugin in another Game in unity3d, but now don't work,
  any additional information will be very helpful.</p>