Ember 3.2 not routing request to .NET Core 2.1 JSON web API

I am new to using Ember and have been following an online video tutorial (see weblink below, though its dated as it uses .NET Core 1.0) that demonstrates how to setup a JSON API back-end with an Ember front-end - I am using Visual Studio Code. I have successfully completed the first video and receive responses from the JSON API back-end. However, I am unable to get the second video working by having Ember send a request to the api-back end for data retrieval. I know this because I am monitoring the calls to the server. So, while I can hit the back-end server and receive a JSON response, the front-end response is HTTP Error 404 - page not found and there is no request to the back-end.

My best guess is that changes have been made to .NET Core and Ember with respect to routing that are not covered in the videos. Unfortunately, a 404 error is very little to go on and I am unable to find the problem. Does anybody know where the problem is or how I can troubleshoot this?

Video tutorial: https://www.youtube.com/watch?v=_d53rG2i9pY&index=2&list=PLu4Bq53iqJJAo1RF0TY4Q5qCG7n9AqSZf

router.js

import EmberRouter from '@ember/routing/router';
import config from './config/environment';

const Router = EmberRouter.extend({
  location: config.locationType,
  rootURL: config.rootURL
});

Router.map(function() {
  this.route('todo-items');
});

export default Router;

environment.js

'use strict';

module.exports = function(environment) {
  let ENV = {
    modulePrefix: 'todo-list-client',
    environment,
    rootURL: '/',
    locationType: 'auto',
    EmberENV: {
      FEATURES: {
        // Here you can enable experimental features on an ember canary build
        // e.g. 'with-controller': true
      },
      EXTEND_PROTOTYPES: {
        // Prevent Ember Data from overriding Date.parse.
        Date: false
      }
    },

    APP: {
      host: 'http://localhost:5000',
      namespace: 'api/v1'
    }
  };

  if (environment === 'development') {
    // ENV.APP.LOG_RESOLVER = true;
    // ENV.APP.LOG_ACTIVE_GENERATION = true;
    // ENV.APP.LOG_TRANSITIONS = true;
    // ENV.APP.LOG_TRANSITIONS_INTERNAL = true;
    // ENV.APP.LOG_VIEW_LOOKUPS = true;
  }

  if (environment === 'test') {
    // Testem prefers this...
    ENV.locationType = 'none';

    // keep test console output quieter
    ENV.APP.LOG_ACTIVE_GENERATION = false;
    ENV.APP.LOG_VIEW_LOOKUPS = false;

    ENV.APP.rootElement = '#ember-testing';
    ENV.APP.autoboot = false;
  }

  if (environment === 'production') {
    // here you can enable a production-specific feature
  }

  return ENV;
};

todo-items.js

import Route from '@ember/routing/route';

export default Route.extend({
    model(){
        return this.store.findAll('todo-item');
    }
});