the library listed on the doc page for Authentication

https://api.stackexchange.com/js/2.0/all.js

ultimately redirects to

https://api-v2cdn.sstatic.net/js/all.js

which results in varying degrees of failure. sometimes simple 404 but i am currently getting

This webpage is not available
The webpage at https://api-v2cdn.sstatic.net/js/all.js might be temporarily down or it may have moved permanently to a new web address.
Error 111 (net::ERR_TUNNEL_CONNECTION_FAILED): Unknown error