I'm trying to intall NPM (npm install) and it just seems to hang when retrieving things from registry.npmjs.org/, eg: registry.npmjs.org/babel-jest. If I paste the URL into my browser, it seems to load fine. I can curl www.google.com fine too, so I doubt it's a proxy thing (can also clone from Github too). 
Also, if I restart the install it will hang again but on a different registry.npmjs.org/ file each time.
Why is this and what can I do to fix it?