Proxy authentication in transparent mode

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”.


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.