411 Length Required — Causes & Fix
HTTP 411 (Length Required) means the server refuses the request because it lacks a Content-Length header.
- Applies to
- Any website or web server (HTTP standard)
- Time to fix
- 5–30 minutes
What it means
Causes include a client sending a body without declaring its length, or a server that requires Content-Length. HTTP status 411 is defined in RFC 9110 (HTTP Semantics). This is a client-side (4xx) error — the request itself had a problem, so the fix is usually on the requester's side or in how the server validates the request.
Symptoms
- "411 Length Required" on POST/PUT
- Request with a body is rejected
How to fix it
- 1
Send Content-Length
1. Ensure the client includes a Content-Length header with the body size.
- 2
Adjust the client (developers)
1. Configure the HTTP client/library to send the length, or use chunked encoding where supported.
Frequently asked questions
What triggers 411?
The server needs to know the body size up front. Add a Content-Length header (or use a client that sets it automatically).
Last updated July 20, 2026
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