Exceeded MaxStartups\r\n

HTTP/1.1 403 Forbidden 
Content-Type: text/plain; charset=utf-8
Proxy-Authenticate: Basic realm=""

errorMsg: Unsupported protocol

HTTP/1.1 407 Proxy Authentication Required 
Content-Type: text/plain; charset=utf-8
Proxy-Authenticate: Basic realm="proxy"

errorMsg: HTTP/1.1 %s Proxy Authentication Required\r\nProxy-Authenticate: Basic realm=\"\"\r\n\r\nProxy Authentication Required

HTTP/1.1 407 Proxy Authentication Required
Proxy-Authenticate: Basic realm=""

HTTP/1.1 407 Proxy Authentication Required
Proxy-Authenticate: Basic realm=""

Proxy Authentication Required