I'm running version 11.0.27011.711 I can't get the 3CX license to activate via an HTTP proxy server. This is the first one I've had to do this way. The Proxy settings are in and I can browse the web with no problems. I've tried allowing unfiltered access etc but all I get is an error about specifying the proxy settings. So I'm assuming (dangerous I know) it can be done this way. I have seen a couple of issues on forums regarding different versions of 3cx.