This article lists standard and notable non-standard HTTP response status codes. Standardized codes are defined by IETF as documented in Request for Comments (RFC) publications and maintained by the IANA. The 504 Gateway Timeout error occurs when a browser's HTTP request to the server doesn't respond in time, preventing it from being completed. The HTTP 504 Gateway Timeout server error response status code indicates that the server, while acting as a gateway or proxy, did not get a response in time from the upstream server in order to complete the request. 504 Gateway Timeout Error (What It Is and How to Fix It) - Life… Want to get more free help on using Calc? You can, by signing up for my Calc Crash Course! In most cases of 502 / 504errors, back-end servers are not communicating correctly. When this happens, you will see color page with Cloudflare branding and the Error 502 Bad Gateway or Error504 Gateway Timeout. So, why exactly are we seeing this 504 Gateway Timeout error, especially during the initial silent refresh? It's a bit of a puzzle. When you get a 504, it basically means one server didn't get a response in time from another server it neededto access. The 502 bad gateway error means that the server received an invalid response from an inbound server. Check out these common causes and solutions.Learn how to fix the 504 Gateway Timeout errorcode on your site. Simple, easy to follow solutions to bring your site back online.