What does 504 Gateway Timeout mean?

The "504 Gateway Timeout" status code is an HTTP response indicating that a server, acting as a gateway or proxy, did not receive a timely response from an upstream server it needed to access to complete the request. This typically happens when the upstream server is slow or unavailable, leading to a timeout error.

For example, if a website relies on an external API to fetch data and that API is taking too long to respond, the server may return a 504 Gateway Timeout error. This error is often temporary and may be caused by server overload, network issues, or problems with the upstream service. It notifies the user that the server could not complete the request within the expected timeframe.