Are you sure? Our private proxies only allow access to 5 websites; Facebook, Google, Instagram, YouTube & LinkedIn (and their subdomains). Are you trying to reach one of those 5 websites?
What happens if you use the proxy in a browser (FireFox for instance) and try to visit one of those 5 websites? If it works you know the proxy is working fine and something else is causing the problem.
If you tried everything but still think your proxies are not working please send us a message to support with the browser/software you are using and the website you are trying to reach.