Is your machine controlled by a system admin at work? Do you know if they need to whitelist any URL? It's possible that to support Google Web Designer, they whitelisted
https://www.gstatic.com/ninja/beta. Starting in 1.8.0 release that we launched in May of this year, we decoupled the templates from the web app so the templates are stored in
https://www.gstatic.com/ninja/templates instead and this URL will also need to be whitelisted too in some network configuration.