SNSExample gets crashed after calling AWSSDK.Examples.GCM.Register(...) method.

Hi there,

I'm playing with SNSExample but it gets crashed when tested on Nexus 5x.

That happened right after calling AWSSDK.Examples.GCM.Register(...) method but I couldn't figure out what was wrong since it did not provide any stacktrace information.
It only says "FATAL EXCEPTION". that's it.
Here is the log.
03-31 18:54:03.634 3939-5563/? D/GCM: GcmService start Intent { act=com.google.android.c2dm.intent.REGISTER pkg=com.google.android.gms cmp=com.google.android.gms/.gcm.GcmService (has extras) } com.google.android.c2dm.intent.REGISTER
03-31 18:54:03.884 25366-25366/myapp.share D/AndroidRuntime: Shutting down VM
03-31 18:54:03.890 25366-25397/myapp.share I/AWSUnityGCMWrapper: Saving regId on app version 1
03-31 18:54:03.900 25366-25397/myapp.share I/Unity: regId = APA91bH343lkjDfPiep970Jay95y-bKygVTRlcK0I4mdEREJkjkl3342uldN9LlhArRfJuwKHBe89YM4DXcS5UXP1qPPVM1qDlzbPxukbV7cLBzWzdB2EMRELKEmFDKFJEREi8VT-W0
UnityEngine.DebugLogHandler:Internal_Log(LogType, String, Object)
UnityEngine.DebugLogHandler:LogFormat(LogType, Object, String, Object[])
UnityEngine.Logger:Log(LogType, Object)
UnityEngine.Debug:Log(Object)
AWSSDK.Examples.GCM:Register(Action`1, String[]) (at C:\Users\user1\Documents\personal\projects\Share\Assets\Examples\GCM.cs:36)
AWSSDK.Examples.SNSExample:RegisterDevice() (at C:\Users\user1\Documents\personal\projects\Share\Assets\Examples\SNSExample.cs:103)
UnityEngine.Events.InvokableCall:Invoke(Object[]) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:144)
UnityEngine.Events.InvokableCallList:Invoke(Object[]) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:621)
UnityEngine.Events.UnityEventBase:Invoke(Object[]) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:756)
UnityEngine
03-31 18:54:03.902 25366-25366/myapp.share E/AndroidRuntime: FATAL EXCEPTION: main
Process: myapp.share, PID: 25366
java.lang.Error: FATAL EXCEPTION [main]
Unity version : 5.3.4f1
Device model : LGE Nexus 5X
Device fingerprint: google/bullhead/bullhead:6.0.1/MMB29P/2473553:user/release-keys

I'm using Unity 5.2.4f1.

Cheers