What does the 5XX group of HTTP status codes indicate?

3XX codes indicate redirection, meaning the client must take additional action such as following a new URL to complete the request.

2XX codes indicate successful responses, such as 200 OK, where the request was received and fulfilled by the server.

4XX codes indicate client errors, such as 404 Not Found or 400 Bad Request, where the fault lies in the client's request.

The 5XX class of HTTP status codes indicates that the server encountered an error or is incapable of fulfilling a valid request. Examples include 500 Internal Server Error and 503 Service Unavailable, both of which reflect failures in server-side processing rather than problems with the client request.