407 Proxy Authentication Required

407 Proxy Authentication Required

This code is similar to 401 (Unauthorized), but indicates that the client must first authenticate itself with the proxy. The proxy MUST return a Proxy-Authenticate header field ([RFC 2068], section 14.33) containing a challenge applicable to the proxy for the requested resource. The client MAY repeat the request with a suitable Proxy-Authorization header field ([RFC 2068], section 14.34). HTTP access authentication is explained in "HTTP Authentication: Basic and Digest Access Authentication" [43].