React Boilerplate cannot be run with "npm run start"

Question

After a fresh checkout of react-boilerplate and running

npm run setup

and

npm run start

It stops with an error message similar to this:

npm ERR! node v6.10.3
npm ERR! npm  v3.10.10
npm ERR! code ELIFECYCLE
npm ERR! [email protected] start: `cross-env NODE_ENV=development node server`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] start script 'cross-env NODE_ENV=development node server'.
npm ERR! Make sure you have the latest version of node.js and npm installed.

Answer 1

Turns out the solution was (in my case) very simple:

Make sure no other react boilerplate dev server is running on the same ports.

I halted the other running one and it worked.

HTH and spare someone an hour of looking through actual npm/react-boilerplate issues.