create-react-app does not serve boilerplate app

Question

I haven't made any changes, I just run "create-react-app client", then everything runs correctly, I cd into the directory and run "yarn start". Then I have two problems: 1) It says "Something is already running on port 3000". Unfortunately when I use lsof and netstat, nothing is running on port 3000. I say to run on a different port, and it then attempts to serve the app. 2) Nothing is served on the new port. The browser opens up, the console gives no errors, but nothing gets served to the browser.

node version 8.7.0 yarn version 1.3.2 create-react-app version 1.3.3 OS MacOS

Answer 1

My hosts file was empty, so "localhost" didn't mean anything. 127.0.0.1 localhost fixed it.