title: keep getting "? Something is already running on port 3000" when I do npm start on react app
body: <p>I keep on getting &quot;? Something is already running on port 3000&quot; message in my terminal when I start up my react server when there is absolutely nothing running on my port 3000</p>
  <p>What I have tried to solve with:</p>
  <ol>
  <li>Restart the macOS.</li>
  <li>checking my &quot;http://localhost:3000&quot; on chrome browser. (Nothing: This site can’t be reached)</li>
  <li>Go to chrome://serviceworker-internals and chrome://appcache-internals, search for localhost:3000 (Nothing found)</li>
  <li>I also tried almost every command lines I found on Google regarding this issue</li>
  <li>I also created another express.js app, and it was successfully launch on port 3000 while React said there is something running on 3000. React on my computer just keeping thinking there is something running on port 3000.</li>
  </ol>
  <p><img src="https://i.stack.imgur.com/RfGE1.png" alt="terminal" /></p>
  <p><img src="https://i.stack.imgur.com/nsITN.png" alt="Chrome" /></p>