title: I always get "something is already running on port 3000" whenever I do npm start on react app
body: <p>Today I was trying to create a fake rest api with express js and deployed my api to heroku
  I am so new to this and followed the youtube video.
  And in the app.js file i typed below</p>
  <pre><code>app.listen(process.env.PORT || 3000, () =&gt; {
      console.log(&quot;server is working&quot;)
  })
  </code></pre>
  <p>but now whenever i create a new react app and run npm start, i get &quot;something is already running on port 3000&quot; error.
  I tried below solutions from what i searched but none of these worked. I use WINDOWS 10 as my operating system.</p>
  <ol>
  <li>I changed the port from 3000 to 4200 in the express.js and pushed it however did not change.</li>
  <li>i ended the task from task manager for node.js-server-javascript and did not work</li>
  <li>i tried npx kill-port 300 and did not work ( it says the command kill-port is not found )</li>
  <li>i opened command line as administrator and typed below commands</li>
  </ol>
  <pre><code>netstat -a -o -n
  taskkill /F /PID PID_of_port
  </code></pre>
  <pre><code>netstat -ano | find &quot;3000&quot;
  taskkill -f -pid 27692
  </code></pre>
  <p>But i get below error although I opened the command line as administrator</p>
  <p>ERROR: The process with PID 27692 could not be terminated.
  Reason: Access denied.</p>
  <p>How can i solve this issue ?</p>