5xx Server ErrorHTTP Status Code Reference

HTTP 510 Not Extended— What It Means, Causes & How to Fix It

The server requires further extensions to the request in order to fulfill it. The server provides information about the extensions it requires in the response.

Live URL Status Checker

Enter any URL to see its real HTTP response code

Common Causes

  • Server requires an HTTP extension not included in the request
  • Missing mandatory extension header
  • Client not supporting a required server extension

How to Fix

  1. 1Add the required extension headers to your request
  2. 2Check server documentation for required extensions
  3. 3Update your HTTP client to support the needed extensions

Example

HTTP 510 Not Extended
GET /resource HTTP/1.1

→ 510 Not Extended
→ "This resource requires the Foo-Extension header"

Related Server Error Codes

500

Internal Server Error

501

Not Implemented

502

Bad Gateway

503

Service Unavailable

504

Gateway Timeout

505

HTTP Version Not Supported

506

Variant Also Negotiates

507

Insufficient Storage

508

Loop Detected

511

Network Authentication Required

Commonly Referenced Status Codes

The most frequently searched HTTP status codes

200OK201Created204No Content301Moved Permanently302Found400Bad Request401Unauthorized403Forbidden404Not Found422Unprocessable Content429Too Many Requests500Internal Server Error502Bad Gateway503Service Unavailable504Gateway Timeout

Related Tools

HTTP Status LookupAPI Request BuildercURL GeneratorHTTP Header ViewerHTTP Header DiffRedirect Checker