Some educational and corporate networks block Ethereum mining (as well as other cryptocurrencies). The most common way mining is blocked is either by restricting outgoing ports, or directly blocking the hostnames of popular mining pools.
It is possible to bypass these network restrictions through the use of proxies or VPN tunnels, but it is critical to have a low latency solution to avoid stale shares.
As of version 1.5.6 WinEth has an experimental feature which uses a hosted Socks5 tunnel to direct all your traffic over port 443 so it looks like normal internet traffic. This traffic goes through a server hosted by us and is then forwarded to the mining pool (either Nanopool or Ethermine).
Enable this feature by checking the box in the advanced settings of WinEth.
As this is a new preview feature we can not guarantee the availability or performance of the proxy server.