Android Studio minimum SDK API 19: Android 4.4(KitKat) Firebase Authentication Crashes on Start-up

Question

I am trying to develop a firebase authentication login activity application in android studio by using android 4.4(KitKat) version. When I build my application in android studio my application builds with no problem. But when I install my application on my android 5 device my application crashes on start-up. Actually when I write and build the same code in android studio by using android 7.0(nougat) version my application builds and installs on my android 11 device and it does not crash on start-up. I mean I need to know if it is possible to use firebase authentication by using android studio android 4.4(KitKat) version. Below is my code:

package com.example.myapplication373947v339;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.content.Intent;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.annotation.NonNull;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;

import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.firestore.FirebaseFirestore;

import com.google.firebase.firestore.CollectionReference;
import com.google.firebase.firestore.DocumentSnapshot;
import com.google.firebase.firestore.QuerySnapshot;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private EditText emailTextView, passwordTextView;
    private FirebaseAuth mAuth;
    private EditText emailTextView2, passwordTextView2;
    private Button Btn2;
    private EditText passwordTextView3;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mAuth = FirebaseAuth.getInstance();
        emailTextView = findViewById(R.id.email);
        passwordTextView = findViewById(R.id.passwd);
        emailTextView2 = findViewById(R.id.email2);
        passwordTextView2 = findViewById(R.id.password);
        Btn2 = findViewById(R.id.login);
        passwordTextView3 = findViewById(R.id.editTextTextPassword5);
        Btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
        //        loginUserAccount();
                Toast.makeText(getApplicationContext(), "Merhaba!", Toast.LENGTH_LONG).show();
            }
        });
    }

    //private void loginUserAccount() {
    //    String email, password;
    //    email = emailTextView2.getText().toString();
    //    password = passwordTextView2.getText().toString();
    //    if (TextUtils.isEmpty(email)) {
    //        Toast.makeText(getApplicationContext(), "Please enter email!", Toast.LENGTH_LONG).show();
    //        return;
    //    }
    //    if (TextUtils.isEmpty(password)) {
    //        Toast.makeText(getApplicationContext(), "Please enter password!", Toast.LENGTH_LONG).show();
    //        return;
    //    }
    //    mAuth.signInWithEmailAndPassword(email, password)
    //            .addOnCompleteListener(
    //                    new OnCompleteListener<AuthResult>() {
    //                        @Override
    //                        public void onComplete(@NonNull Task<AuthResult> task) {
    //                            if (task.isSuccessful()) {
    //
    //                                Toast.makeText(getApplicationContext(), "Login successful!!", Toast.LENGTH_LONG).show();
    //                                Intent intent
    //                                        = new Intent(MainActivity.this, MainActivity2.class);
    //                                startActivity(intent);
    //
    //                            } else {
    //
    //                                Toast.makeText(getApplicationContext(), "Login failed!!", Toast.LENGTH_LONG).show();
    //
    //                            }
    //                        }
    //                    });
    //
    //
    //}
}

When I remove mAuth = FirebaseAuth.getInstance(); code fragment my application does not crash on start-up. But when I add this code fragment my application crashes. I need to know the reason for this.