Use a VPN service → You may try to change the original DNS servers in your network adapter.
VPN is much better than a free web proxy, and it works with any website.
Stop searching for it, check this page: Best VPN provider of 2016 → Is possible that in some cases you cannot access because a web toolbar or a spyware has modified your web browser's proxy settings.
Is blocked in your school, in your country or in your computer ?
This web proxy server may allow you to access in case it is blocked in your PC.
How to reset proxy settings of web browsers → If this web proxy does not work, you may try to use other web proxy servers, for example websiteproxy2or or to see if you can access via those new web proxies.
Some websites may ban the IP address of some popular web proxies, so in this case you just need to change the web proxy with a new one and check if it works.