HTTP Status Code 431 indicates Request Header Fields Too Large which means that the server is unable to process the request due to the size of one or more request header fields exceeding its limits. This status code falls under the Client Error category, alerting the client that their request cannot be fulfilled as is. When a client sends a request with excessively large headers—perhaps due to a large cookie size, extensive user-agent strings, or other headers—the server will respond with HTTP Status Code 431 to signal that it cannot handle the request in its current form. Clients encountering this status code should consider reducing the size of their request headers before trying again. This helps ensure efficient communication and resource usage on the server, allowing it to remain responsive to other incoming requests.