449 Retry With

HTTP response status code 449 Retry With is an unofficial client error specific to the Microsoft IIS web server. The server returns this code to indicate the request lacks required information and the client needs to retry with the missing data.

Table of Contents

Usage

The 449 Retry With status code tells the client to determine what information is missing, reformulate the request, and resubmit. The response typically includes a header or body describing the additional data the server expects, such as an Authentication token or extended session parameter.

This code is documented in the Microsoft Web Distributed Authoring and Versioning (WebDAV) extensions for IIS.

Note

The reason phrase varies across Microsoft documentation. The MS-WDV specification ABNF uses "Reply With" while other references use "Retry With." Both forms appear in practice.

SEO impact

Search engines like Google do not index a URL with 449 Retry With response status. URLs previously indexed with this code are removed from search results.

Example

A client sends a POST request to an IIS server. The server responds with 449 Retry With because the request is missing required extended information.

Request

POST /resource HTTP/1.1
Host: www.example.re
Content-Type: application/xml
Content-Length: 45

<request><action>create</action></request>

Response

HTTP/1.1 449 Retry With
Content-Type: text/html
Content-Length: 165

<html>
  <head>
    <title>Retry With</title>
  </head>
  <body>
   <p>The request is missing required information.
   Resubmit with the correct parameters.</p>
  </body>
</html>

How to fix

Inspect the response body for a description of the missing data. IIS returns an entity body explaining the exact fields, tokens, or extended parameters the server expects before completing the request.

Look for the Ms-Echo-Request header in the 449 response. The Microsoft WebDAV protocol extension uses this header to instruct the client on what data to include. The client must resubmit the original request with an Ms-Echo-Reply header containing the requested value.

Verify Authentication credentials and tokens. WebDAV operations on IIS require proper authentication. Anonymous Authentication alone is insufficient for WebDAV resources. Enable Windows Authentication or Basic Authentication in the IIS Manager for the target site or virtual directory.

Check IIS request validation settings. Request filtering rules or custom request validators block requests missing required parameters and return 449 instead of a standard 400 or 401.

Ensure the client sends all extended headers the application expects. Custom IIS applications sometimes validate for proprietary headers and return 449 when headers are absent. Review the IIS application logs (under %SystemDrive%\inetpub\logs\LogFiles) for entries tagged with substatus code details.

Standard HTTP clients do not handle 449 responses automatically. Client code interacting with IIS WebDAV endpoints needs explicit retry logic for this status code.

Takeaway

The 449 Retry With status code is a Microsoft IIS client error sent when the client has not supplied all required information to complete the request.

See also

Last updated: March 5, 2026