411 Length Required
The server refuses the request because it lacks a Content-Length header.
What it means
HTTP 411 Length Required means the server will not accept a request that has a body but no Content-Length header. Some servers insist on knowing the size of the payload up front rather than reading an unbounded stream, and they reject the request until the client states the length.
When it happens
It happens when a client sends a POST or PUT without a Content-Length, often from a hand-rolled HTTP request or a misconfigured client that streams a body without declaring its size.
How to fix it
- Add an accurate Content-Length header to the request.
- If the body is generated on the fly, buffer it so its length is known, or use chunked transfer encoding where the server supports it.
- Check the HTTP client library is not stripping the header before the request goes out.
SEO impact
None for normal pages. It affects request bodies, and crawlers fetch pages with simple GET requests that have no body.
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Related codes
The server could not understand the request due to malformed syntax.
401 UnauthorizedAuthentication is required and has failed or not been provided.
402 Payment RequiredA largely reserved code intended for payment-gated access to a resource.
403 ForbiddenThe server understood the request but refuses to authorize it.
404 Not FoundThe server could not find the requested resource.
405 Method Not AllowedThe HTTP method used is not supported for the requested resource.
Related guides
A plain-English primer on HTTP status codes for SEOs: what the 2xx, 3xx, 4xx, and 5xx families mean, which ones affect rankings, and the codes worth knowing.
How to find and fix broken linksA practical walkthrough for finding broken links on your site, working out why each one breaks, and fixing them so visitors and crawlers stop hitting dead ends.