Firebase Erreur Permission denied

Je suis Très débutant à firebase et essayer d'obtenir la valeur de ma base de données.

mais il en me montrant même erreur à chaque fois.

    W/SyncTree: Listen at /child failed: FirebaseError: Permission denied

Mon firebase règles

    {
  "Condition" : "sunny",
  "child" : 5
}

mon Androidmanifest.xml

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mohit.firebase" >

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        >
        <activity android:name=".MainActivity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Mon mainactivity.java
package com.mohit.firebase;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.firebase.client.DataSnapshot;
import com.firebase.client.Firebase;
import com.firebase.client.FirebaseError;
import com.firebase.client.ValueEventListener;
public class MainActivity extends AppCompatActivity {
TextView tv;
Button bt1;
Button bt2;
Firebase mRootRef;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView) findViewById(R.id.button);
bt1 = (Button) findViewById(R.id.button);
bt2 = (Button) findViewById(R.id.button2);
Firebase.setAndroidContext(this);
mRootRef = new Firebase("https://superb-flag-126719.firebaseio.com/");
Log.d("fb","Firebase Object: "  + String.valueOf(mRootRef));
}
@Override
protected void onStart() {
super.onStart();
Firebase mchild = mRootRef.child("child");
mchild.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
String condition = (String) dataSnapshot.getValue();
Log.d("fb","String get: " + condition);
tv.setText(condition);
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});
}
}

mon BuildGraddle

    apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "23.0.2"
defaultConfig {
applicationId "com.mohit.firebase"
minSdkVersion 16
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
packagingOptions {
exclude 'META-INF/LICENSE'
exclude 'META-INF/LICENSE-FIREBASE.txt'
exclude 'META-INF/NOTICE'
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.1.1'
compile 'com.firebase:firebase-client-android:2.5.2+'
}

j'ai vérifié mon firebase url. Il est Parfaitement Correct.