What is 421 headers?

421 headers refer to a specific type of HTTP status code that is returned by a server to a client during web communications. Specifically, a 421 header means that the server has been asked to connect too many times and has refused the connection attempt.

A 421 response code is often used in situations where a client is trying to access a resource or page too frequently, violating the server's rules about the number of requests that can be made in a specific time period. When this happens, the server will send a 421 error to the client, which will then stop the connection attempt.

In some cases, a 421 header might also be used to indicate that a server is overloaded or experiencing technical difficulties, and is unable to process a particular request at that time. In this situation, the client would typically need to wait and try again later, once the server has resolved the issue.

Overall, 421 headers are a useful tool for ensuring that web communications remain reliable and efficient, by allowing servers to effectively manage the number and frequency of connections that are being made.