Ничто не спасает в Firebase

Question

Я довольно новичок в создании приложений с Android Studio. Я получил рекомендацию следовать учебнику, что я и сделал. Все было хорошо, пока я не запустил программу, и по какой-то причине ничего не сохранилось в Firebase.

package com.hossain.mylearningproject;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
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 com.google.firebase.database.ValueEventListener;

import java.util.HashMap;

public class RegisterActivity extends AppCompatActivity {

private Button CreateAccountBtn;
private EditText Inputname, InputPhoneNumber, InputPassword;
private ProgressDialog LoadingBar;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);

    CreateAccountBtn = (Button) findViewById(R. id. register_btn);
    Inputname = (EditText) findViewById(R. id. register_username_input);
    InputPhoneNumber = (EditText) findViewById(R. id. register_phone_number_input);
    InputPassword = (EditText) findViewById(R. id. register_password_input);
    LoadingBar = (ProgressDialog) new ProgressDialog(this);

    CreateAccountBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            CreateAccount();
        }
    });
}


private void CreateAccount(){
    String name = Inputname.getText().toString();
    String phonenumber = InputPhoneNumber.getText().toString();
    String password = InputPassword.getText().toString();

    if (TextUtils.isEmpty(name)){
        Toast.makeText(this, "Please Write you're name...", Toast.LENGTH_SHORT).show();
    }
    else if (TextUtils.isEmpty(phonenumber)){
        Toast.makeText(this, "Please Write you're phone number...", Toast.LENGTH_SHORT).show();
    }
    else if (TextUtils.isEmpty(password)){
        Toast.makeText(this, "Please Write you're Password...", Toast.LENGTH_SHORT).show();
    }
    else{
        LoadingBar.setTitle("Create account");
        LoadingBar.setMessage("Please wait while we check the credentialls.");
        LoadingBar.setCanceledOnTouchOutside(false);
        LoadingBar.show();

        ValidateCredentialls(name, phonenumber);
    }
}

private void ValidateCredentialls(final String name, final String phonenumber){
    final DatabaseReference Rootref;
    Rootref = FirebaseDatabase.getInstance().getReference();
    Rootref.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            if (!(dataSnapshot.child("Users").child(phonenumber).exists())){
                HashMap<String, Object> Userdatamap = new HashMap<>();
                        Userdatamap.put("phone number", phonenumber);
                        Userdatamap.put("Username", name);
                        Userdatamap.put("password", InputPassword);

                        Rootref.child("Users").child(phonenumber).updateChildren(Userdatamap)
                                .addOnCompleteListener(new OnCompleteListener<Void>()
                                {
                                    @Override
                                    public void onComplete(@NonNull Task<Void> task)
                                    {
                                        if(task.isSuccessful())
                                        {
                                            Toast.makeText(RegisterActivity.this, "Congratulations, you're account has now been created", Toast.LENGTH_SHORT).show();
                                            LoadingBar.dismiss();

                                            Intent intent = new Intent(RegisterActivity.this, LoginActivity.class);
                                            startActivity(intent);

                                        }
                                        else
                                            {
                                            LoadingBar.dismiss();
                                            Toast.makeText(RegisterActivity.this, "Connection problem, Please check you're internet connection.", Toast.LENGTH_SHORT).show();
                                        }
                                    }
                                });
            }
            else
                {
                Toast.makeText(RegisterActivity.this, "An account with " + phonenumber + " already exists", Toast.LENGTH_SHORT).show();
                LoadingBar.dismiss();
                Toast.makeText(RegisterActivity.this, "Please try again using a diffrent phone number", Toast.LENGTH_SHORT).show();

                Intent intent = new Intent(RegisterActivity.this, MainActivity.class);
                startActivity(intent);
            }
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });
}
}