title: React Native cannot access express backend
body: <p>I have made a REST API for my react native application and want to fetch data from it, though this is not possible for me.</p>
  <p>I have tried using localhost and ipv4 as the url, but it doesn't help at all. I also get an &quot;Network Error&quot; at times when I change to the different URLs, which I don't fully understand why they show up, since ipv4 or localhost should work.</p>
  <p>I usually get a warning about the metro server after a while, if that has anything to do with it.</p>
  <p>How can I connect my React Native client to my express backend?</p>