Error:  504 Gateway Error
You are receiving a 504 Gateway Error

Troubleshooting 504 Gateway Errors

A 504 Gateway Error indicates that the proxy was unable to make a connection to a gateway. Receipt of this error message, or exception, indicates that a connection could not be established to a forwarding or SOCKS gateway. If verification is necessary, a packet capture can be used to verify that the forward host is unresponsive.

A 504 Gateway Error can also be displayed if a loop occurs in a proxy chain. Blue Coat proxies will add a 'Via' header to server side requests which is used to determine if a proxy receives a request that originated from itself. If a proxy receives a request with a 'Via' header that it recognizes it will not propagate the request to prevent the loop. It will instead return a 504 Gateway Error.