Cannot get data from an Node API

I have an API (Localhost:3000) using node and a front end (Localhost:4200) using Angular 6. Using my regular chrome browser, I am able to CRUD to the database in the API but when I use the android emulator using (10.0.2.2:4200), I cannot do any of the CRUD to the database anymore. Please see my codes below:

Node [index.js]

const express   = require("express");
const nedb      = require("nedb");
const rest      = require("express-nedb-rest");
const cors      = require("cors");

const app = express();

const datastore = new nedb({
    filename: "mycoffeeapp.db",
    autoload: true
});

const restAPI = rest();
restAPI.addDatastore('coffees', datastore);

app.use(cors());
app.use('/', restAPI);

app.listen(3000);

angular front end This is in the data.service

import { Injectable } from "@angular/core";
import { HttpClient } from "@angular/common/http";

@Injectable({
  providedIn: "root"
})
export class DataService {
  public endpoint = "http://localhost:3000";


  constructor(
    private http: HttpClient
  ) {}

  getList(callback) {
    this.http.get(`${this.endpoint}/coffees`)
      .subscribe(response => {
        callback(response);
      });
  }

  get(coffeeId: string, callback) {
    this.http.get(`${this.endpoint}/coffees/${coffeeId}`)
      .subscribe(response => {
        callback(response);
      });
  }

  save(coffee, callback) {
    if (coffee._id) {
      this.http.put(`${this.endpoint}/coffees/${coffee._id}`, coffee)
        .subscribe(response => {
          callback(true);
        });
    } else {
      this.http.post(`${this.endpoint}/coffees`, coffee)
      .subscribe(response => {
        callback(true);
      });
    }
  }
}

in the component:

constructor(
    private data: DataService,
    private router: Router,
    private gls: GeoLocationService
  ) { }

  ngOnInit() {
    this.data.getList(list => {
      this.list = list;
    });
  }