quickstart-android: Unknown Source In Firebase On Android When Request Forgot Password Email

The Error:

12-21 15:46:56.137 19795-19795/renderresults.com.wheresmycar E/AndroidRuntime: FATAL EXCEPTION: main
                                                                               Process: renderresults.com.wheresmycar, PID: 19795
                                                                               java.lang.IllegalStateException: Could not execute method for android:onClick
                                                                                   at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
                                                                                   at android.view.View.performClick(View.java:5637)
                                                                                   at android.view.View$PerformClick.run(View.java:22429)
                                                                                   at android.os.Handler.handleCallback(Handler.java:751)
                                                                                   at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                   at android.os.Looper.loop(Looper.java:154)
                                                                                   at android.app.ActivityThread.main(ActivityThread.java:6119)
                                                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                                                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
                                                                                Caused by: java.lang.reflect.InvocationTargetException
                                                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                                                   at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
                                                                                   at android.view.View.performClick(View.java:5637) 
                                                                                   at android.view.View$PerformClick.run(View.java:22429) 
                                                                                   at android.os.Handler.handleCallback(Handler.java:751) 
                                                                                   at android.os.Handler.dispatchMessage(Handler.java:95) 
                                                                                   at android.os.Looper.loop(Looper.java:154) 
                                                                                   at android.app.ActivityThread.main(ActivityThread.java:6119) 
                                                                                   at java.lang.reflect.Method.invoke(Native Method) 
                                                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
                                                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 
                                                                                Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.tasks.Task com.google.android.gms.common.api.GoogleApi.zzb(com.google.android.gms.common.api.internal.zzdd)' on a null object reference
                                                                                   at com.google.android.gms.internal.zzdvv.zzb(Unknown Source)
                                                                                   at com.google.android.gms.internal.zzdwc.zza(Unknown Source)
                                                                                   at com.google.firebase.auth.FirebaseAuth.sendPasswordResetEmail(Unknown Source)
                                                                                   at com.google.firebase.auth.FirebaseAuth.sendPasswordResetEmail(Unknown Source)
                                                                                   at renderresults.com.wheresmycar.ForgotPassword.Enter(ForgotPassword.java:30)
                                                                                   at java.lang.reflect.Method.invoke(Native Method) 
                                                                                   at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
                                                                                   at android.view.View.performClick(View.java:5637) 
                                                                                   at android.view.View$PerformClick.run(View.java:22429) 
                                                                                   at android.os.Handler.handleCallback(Handler.java:751) 
                                                                                   at android.os.Handler.dispatchMessage(Handler.java:95) 
                                                                                   at android.os.Looper.loop(Looper.java:154) 
                                                                                   at android.app.ActivityThread.main(ActivityThread.java:6119) 
                                                                                   at java.lang.reflect.Method.invoke(Native Method) 
                                                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
                                                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

my build.gradle (project)

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.0-beta7'
        classpath 'com.google.gms:google-services:3.1.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

build.gradle (app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion "27.0.2"
    defaultConfig {
        applicationId "renderresults.com.wheresmycar"
        minSdkVersion 25
        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 'com.google.firebase:firebase-core:11.8.0'
    compile 'com.google.firebase:firebase-auth:11.8.0'
    implementation 'com.google.android.gms:play-services-maps:11.8.0'
    implementation 'com.google.android.gms:play-services-location:11.8.0'
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation('com.android.support.test.espresso:espresso-core:3.0.1', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
}
apply plugin: 'com.google.gms.google-services'

Code

package renderresults.com.wheresmycar;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.FirebaseAuth;

public class ForgotPassword extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.forgot_password);
    }
    public void Enter(View view) {
        FirebaseAuth auth = FirebaseAuth.getInstance();
        final EditText email = findViewById(R.id.editText3);
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        FirebaseAuth.getInstance().sendPasswordResetEmail(email.getText().toString())
                .addOnCompleteListener(new OnCompleteListener<Void>() {
                    @Override
                    public void onComplete(@NonNull Task<Void> task) {
                        if (task.isSuccessful()) {
                            Log.d("TAG", "Email sent.");
                            startActivity(new Intent(ForgotPassword.this, MainActivity.class));
                        }
                    }
                });
    }
}