title: net::ERR_CONNECTION_CLOSED in Angular 2 Firebase App
body: <p>I hosted my Node app and MongoDB on a DigitalOcean droplet and Angular App in Firebase. I am able to connect to Node backend from Postman and from my Angular App running locally on port 4200. But when I use my Angular App hosted in Firebase to connect to the Backend in DO Droplet, I get this error in Chrome console.</p>
  
  <p><a href="https://i.stack.imgur.com/Getn5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Getn5.png" alt="Error Message in console"></a></p>
  
  <p>I have added the link of Firebase app in CORS Whitelist Array in Node app, also added backend url in environment.prod.ts file as </p>
  
  <pre><code>backednUrl: 'https://***.**.**.***:3000'
  </code></pre>
  
  <p>The Error log doesn't say much in Specific. How do I fix this error? Is this because of any SSL or HTTPS issue?</p>