c# - RuntimeException throwed after receiving a notification -

i implemented push notifications on c# xamarin.android project in official firebase documentation.

it possible send notifications firebase console. tried send messages c# service. device monitor says, gcm message delivered.

see android device monitor messages: http://imgur.com/a/wnov3

here's code. why happen?

androidmanifest.xml

<application android:label="myapp" android:icon="@drawable/icon">     <receiver android:name="com.google.firebase.iid.firebaseinstanceidinternalreceiver" android:exported="false" />     <receiver android:name="com.google.firebase.iid.firebaseinstanceidreceiver" android:exported="true" android:permission="com.google.android.c2dm.permission.send">   <intent-filter>     <action android:name="com.google.android.c2dm.intent.receive" />     <action android:name="com.google.android.c2dm.intent.registration" />     <action android:name="com.google.firebase.messaging_event"/>     <category android:name="${applicationid}" />   </intent-filter>     </receiver>  <service android:name=".myfirebasemessagingservice">     <intent-filter>         <action android:name="com.google.firebase.messaging_event"/>     </intent-filter> </service> </application> 

myfirebasemessagingservice.cs

[service] [intentfilter(new[] { "com.google.firebase.messaging_event" })] public class myfirebasemessagingservice : firebasemessagingservice {     const string tag = "myfirebasemsgservice";      public myfirebasemessagingservice()     {         log.debug(tag, "service called");     }     public override void onmessagereceived(remotemessage message)     {         string msg = message.getnotification().body;         log.debug(tag, msg);         } } 

i got work manifest configuration

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.xxxxx.xxxx" android:versionname="1.0.0" android:versioncode="2">     <uses-sdk android:minsdkversion="15" />     <uses-permission android:name="android.permission.internet" />     <uses-permission android:name="com.google.android.c2dm.permission.receive" />     <uses-permission android:name="android.permission.wake_lock" />     <application android:icon="@drawable/icon" android:label="xx xxx">         <receiver android:name="com.google.firebase.iid.firebaseinstanceidinternalreceiver" android:exported="false" />         <receiver android:name="com.google.firebase.iid.firebaseinstanceidreceiver" android:exported="true" android:permission="com.google.android.c2dm.permission.send">             <intent-filter>                 <action android:name="com.google.android.c2dm.intent.receive" />                 <action android:name="com.google.android.c2dm.intent.registration" />                 <category android:name="${applicationid}" />             </intent-filter>         </receiver>     </application> </manifest>