449 Retry With
HTTP response status code 449 Retry With is an unofficial client error specific to the Microsoft IIS web server and is returned to indicate that the server can not satisfy the request because the user has not provided the required information.
When the 449 Retry With status code is received, the client must determine what information is required and reformulate the request accordingly before retrying.
Search engines like Google will not index a URL with 449 Retry With response status, and consequently, URLs that have been indexed in the past but are now returning this HTTP status code will be removed from the search results.
The 449 Retry With status code is a client error that is sent by the server when the client has not supplied all of the information required to complete the request.