Proxy authentication in transparent mode

Hello,
I read here that mitmproxy proxy authentication doesn’t work in transparent mode, what’s the matter?
I try to set up it but browsers don’t prompt user for credentials and show the page with error 407 “normally”.

Thanks.

The problem here is that browsers won’t expect or honor a “Proxy Authentication required” message when they expect to have a direct connection to the destination. For reverse proxies we do support basic authentication, but for transparent proxies that’d mean a new authentication dialogue for every single domain.