I cant't recive data from firestore with Angular

I have used the AngularFireList from @angular/fire/database to get data from firestore while the firestore contains data and I can't get any data from it.

import { Injectable } from '@angular/core';
import { AngularFireDatabase, AngularFireList, AngularFireObject } from '@angular/fire/database';
import { Customer } from '../shared/customer.model';

@Injectable({
providedIn: 'root'
})
export class CustomerService {

customersRef: AngularFireList<any>; // Reference to Student data list, its an Observable
customerRef: AngularFireObject<any>; // Reference to Student object, its an Observable too


// Inject AngularFireDatabase Dependency in Constructor
constructor(private db: AngularFireDatabase) { }

getCustomersList() {
this.customersRef = this.db.list('customers');
return this.customersRef;
}


getCustomer(id: string) {
this.customerRef = this.db.object('customers/' + id);
return this.customerRef;
}}




Continue reading...