Thank you for your question. Our backup agent is configurable for use with proxy servers. Right click on the agent icon in your taskbar and choose Settings, and then Proxy Configuration. However, I'm assuming you have already tried this and are still not having any luck. The agent communicates on both ports 80 and 443, can you verify these ports are open? Also are you aware of any Policy Based Routing that may be restricting the communication?
Additionally, please ensure you have external connectivity to the following IP ranges.