The original reporter is behind a NTML-certified proxy. And the following error happens

　The Connection to server is unstable
　Please check your internet connnection
　Error code : 202

It can be that license sever cannot handle NTLM-proxy correctly (the same thing happened to Qt Creator and Qt Design Studio too, and was solved by adding a functionality of letting user manually input proxy credentials when Qt cannot prick them up correctly). Or it can simply be that the proxy blacklists license server. I've asked about what happens if there is no proxy at all, but still haven't heard from original reporter yet.