400 Bad Request - The request cannot be fulfilled due to bad syntax.
401 Unauthorized - The request was a legal request, but the server is refusing to respond to it. For use when authentication is possible but has failed or not yet been provided.
403 Forbidden - The request was a legal request, but the server is refusing to respond to it mostly due to permission issues.
404 Not Found - The requested page could not be found but may be available again in the future.
5xx: Server Error
500 Internal Server Error - It’s a general-purpose error message for when a web server encounters some form of internal error.
502 Bad Gateway - The server was acting as a gateway or proxy and received an invalid response from the upstream server.
503 Service Unavailable - The server is currently unavailable (overloaded or down) 504 Gateway Timeout The server was acting as a gateway or proxy and did not receive a timely response from the upstream server
