XML Http Request: CORS issue

Hi I've been working on an angularjs app on plnkr, and I'm pulling data from a remote server to the app. Initially I had problems accessing the xml file because of the CORS issue, the cross-domain restriction, but I enabled CORS. The app now works on plnkr, but when I try to run it on the browser, the console gives me the same error, except with an additional note at the end.

The error:

`XMLHttpRequest cannot load http://ift.tt/1M35ggf. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access. The response had HTTP status code 403.`

The "the reponse had HTTP status code 403" bit seems to be new. What's going on? Why does it work on plnkr and not in browser? What do I need to do to fix it? Any help is appreciated.