title: Nodejs (express) running but requests not working
body: <p>I run my project backend 'server.js' (express). it's working correctly and without any problem. But I send a request from Postman or another apps, I can not get any response or error. Only loading.
  Sometimes it works fine and I get all requests correctly but after few minutes or hours I cannot get any request responses.
  Please help me. What is cause this problem?
  I'am using Reactjs, Nodejs (express)</p>