The server processes the request and responds with the requested resources. This is how the process works: every time you visit a website in your browser, the browser sends a request to the web server where the site is hosted. Error Codeĥ04 Gateway Timeout504 Gateway Timeout NGINX The first server (typically the main server) times out, waiting for a response from the second server (upstream server).
To simplify it further, this error occurs when two servers are involved in processing a request.