title: Firebase Auth error : Your API key is invalid, please check you have copied it correctly
body: <p>I have this repo</p>
  <p><a href="https://github.com/HosMercury/start-firebase-auth" rel="nofollow noreferrer">Github simple repo </a></p>
  <p>I just want to <strong>connect to firebase to express without using React</strong> ..
  I got this error</p>
  <pre><code>Error: Your API key is invalid, please check you have copied it correctly.
  </code></pre>