Ember CLI and Rails: Error proxying to http://localhost:3000 - ruby-on-rails

Question

I am following this tutorial for Ember CLI and Rails. I am stuck at the point where you are supposed to load the Book model data using the following command in the console:
App.store.findAll('book');
No data is retrieved and the Ember terminal logs show this error:
Error proxying to http://localhost:3000
connect ECONNREFUSED 127.0.0.1:3000
Error: connect ECONNREFUSED 127.0.0.1:3000
at Object.exports._errnoException (util.js:890:11)
at exports._exceptionWithHostPort (util.js:913:20)
at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1061:14)
GET /books - - ms - -
However when I visit http://localhost:3000/books (the Rails backend), I get the correct JSON response with all the books. Why is the Ember app not able to retrieve this data and how can I fix it?

Answer 1

Restart the Rails server with:
rails s --binding 0.0.0.0
then restart the ember server.

Answer 2

There are multiple things you need to watch.
Try setting up in your embers config/environment.js for each environment proper URL and settings. More info here.
ENV.contentSecurityPolicy = {
'default-src': "'none'",
'script-src': "'self'",
'font-src': "'self'",
'connect-src': "'self' http://localhost:3000",
'img-src': "'self' data:",
'style-src': "'self' 'unsafe-inline'",
'media-src': "'self'"
};
And you also need to explain Rails app to accept connection outside of the rails app. CORS. Looks for this gem.