If you can't connect to localhost on port 5000 via telnet (you can download and use PuttY if you don't have telnet installed), then that means that server isn't running.
If you're using a Windows machine, go to your package.json for the server that is running on port 5000 and change this line:
"start": "./node_modules/.bin/concurrently \"./node_modules/.bin/nodemon\" \"npm run client\"",
To this:
"start": "./node_modules/.bin/concurrently \"npm run server\" \"npm run client\"",
Watch your build messages and you should see something similar to the following:
[0] ==> API Server now listening on PORT 5000!
[1] Starting the development server...
[1]
[1] Compiled successfully!
[1]
[1] You can now view chat app in the browser.
[1]
[1] Local: http://localhost:3000/
[1] On Your Network: http://192.168.1.118:3000/
[1]
[1] Note that the development build is not optimized.
[1] To create a production build, use yarn build.