421421 Misdirected Request
The request was directed at a server that is not able to produce a response for the combination of scheme and authority in the request URI.
301The requested resource has been permanently moved to a new URL, and future requests should use the new URL.
The resource URL has changed permanently. This is common after URL restructuring, domain changes, or switching from HTTP to HTTPS. Search engines will update their index to the new URL.
Update your bookmarks and links to point to the new URL found in the Location header. If you control the code, update the URL in your requests. Browsers automatically follow this redirect.
421The request was directed at a server that is not able to produce a response for the combination of scheme and authority in the request URI.
202The request has been accepted for processing, but the processing has not been completed yet.
403The server understood the request but refuses to authorize it. Unlike 401, re-authenticating will not help.
428The server requires the request to be conditional to prevent the 'lost update' problem.
407The client must first authenticate with the proxy before the request can be forwarded to the target server.
501The server does not support the functionality required to fulfill the request.