Вылетает чат на firebase

Хочу освоить firebase. Приложение вылетает сразу же после запуска на телефоне. Но если удаляю весь код из onCreate() все работает. MainActivity:

package com.example.user.messagerfirebase;

import android.app.Fragment;
import android.content.res.Resources;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import com.github.clans.fab.FloatingActionButton;
import com.github.florent37.materialtextfield.MaterialTextField;
import com.google.firebase.analytics.FirebaseAnalytics;
import com.google.firebase.database.ChildEventListener;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity implements 
View.OnClickListener{
    TextView enter;
    MaterialTextField mtf;
    EditText msgText;
    TextView text;
    ListView list;
    MessageAdapter adapter;
    FloatingActionButton fab;
    FirebaseDatabase database;
    DatabaseReference references;
    ChildEventListener childEventListener;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(this);
    list = (ListView) findViewById(R.id.list);
    enter = (TextView) findViewById(R.id.enter);
    mtf = (MaterialTextField) findViewById(R.id.mtf);
    msgText = (EditText) findViewById(R.id.text);
    database = FirebaseDatabase.getInstance();
    references = database.getReference().child("messages");
    if(childEventListener == null) {
    childEventListener = new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
        }
        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String s) {
        }
        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {
        }
        @Override
        public void onChildMoved(DataSnapshot dataSnapshot, String s) {
        }
        @Override
        public void onCancelled(DatabaseError databaseError) {
        }
    };
        references.addChildEventListener(childEventListener);
  }
    List<MessageClass> messages = new ArrayList<>();
    adapter = new MessageAdapter(this, R.layout.item, messages);
}
@Override
public void onClick(View view) {
    switch (view.getId()){
        case R.id.fab:
            MessageClass message = new 
MessageClass(msgText.getText().toString());
            references.push().setValue(message);
            msgText.setText("");
    }
}
}

Log список:

                                                                     adb 
09-13 20:31:48.657 26628-26628/com.example.user.messagerfirebase 
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.user.messagerfirebase, PID: 26628
java.lang.NoSuchMethodError: com.google.firebase.FirebaseApp.zzcnu
at com.google.firebase.database.FirebaseDatabase.getInstance(Unknown Source)
at com.google.firebase.database.FirebaseDatabase.getInstance(Unknown Source)
at 

com.example.user.messagerfirebase.MainActivity.onCreate(MainActivity.java:53)

at android.app.Activity.performCreate(Activity.java:5258)
at 

android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1099)

at 
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2280)
at 
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1264)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5413)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at 

com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:97 0)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:786)
at dalvik.system.NativeStart.main(Native Method)
build.gradle:
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
buildToolsVersion "26.0.0"
defaultConfig {
    applicationId "com.example.user.messagerfirebase"
    minSdkVersion 16
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner 
"android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 
'proguard-rules.pro'
    }
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-
core:2.2.2', {
    exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:26.+'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
compile 'com.google.firebase:firebase-messaging:10.0.1'
compile 'com.github.florent37:materialtextfield:1.0.7'
compile 'com.github.clans:fab:1.6.4'
compile 'com.google.firebase:firebase-database:9.6.0'
testCompile 'junit:junit:4.12'
}

apply plugin: 'com.google.gms.google-services'