Which two HTTP status-code classes indicate errors in REST APIs? (Choose two.)

HTTP status codes are grouped into classes based on their first digit. The 4XX class (Client Error) indicates that the client made a bad request. Examples include 400 Bad Request, 401 Unauthorized, and 404 Not Found. The 5XX class (Server Error) indicates that the server failed to fulfill a valid request. Examples include 500 Internal Server Error and 503 Service Unavailable. The other classes are not error indicators. 1XX (Informational) codes indicate that the request was received and understood. 2XX (Success) codes indicate that the action was successfully received, understood, and accepted. 3XX (Redirection) codes indicate that further action needs to be taken to complete the request.