Getting HTTP Error 407 - Proxy Authentication Required. How Do I Fix This? Alternatively, for a more concise

http error 407 is all about proxy auth, like others said. If you’re on a work network, chances are you need domain creds.

Try formatting your username as *DOMAIN\username* in the proxy auth popup. If that doesn’t work, IT probably has a specific proxy password for ya.

Annoying, but common in corps.