HTTP 510 Not Extended Error - Meaning & Fix

The HTTP 510 Not Extended status code indicates that the server lacks the capability to fulfill the request due to missing extensions. This occurs when the request includes an extension declaration that the server does not support. The server is unable to process the request as specified. This error also may happen when a scraper includes HTTP headers or features that the target server is not configured to handle, such as custom content types, encoding schemes, or content negotiation methods.

Main causes

Client sends a request with an extension declaration that the server does not support.
Server lacks the capability to handle the requested extension as specified in the client's HTTP headers.
Misconfiguration on the server prevents the handling of the specified extension.
Required libraries or modules to process the extension are missing or disabled on the server.

# Request example 
curl -X GET https://sandbox.oxylabs.io/ -H 'Accept: application/xhtml+xml' -H 'Accept-Encoding: gzip, deflate' -H 'User-Agent: Safari/537.36'

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Common fixes

Review the server configuration to ensure that the resource variants are not set to perform content negotiation themselves.
Check and update the content negotiation settings to avoid conflicts between resource variants.
Verify the server's algorithm for selecting resource variants to ensure it does not recursively negotiate.
Simplify the resource variant management to prevent overlap in negotiation roles and responsibilities.

# Response example HTTP/1.1 510 Not Extended Content-Type: text/html; charset=UTF-8 Content-Encoding: gzip Content-Length: 97 510 Not Extended

Not Extended

Further extensions required.

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Common scraping HTTP error codes

401 Unauthorized	403 Forbidden	404 Not found	405 Method not allowed	406 Not acceptable
407 Proxy authentication required	408 Request timeout	409 Conflict	410 Gone	411 Length required
412 Precondition failed	413 Payload too large	414 Uri too long	415 Unsupported media type	416 Range not satisfiable
417 Expectation failed	421 Misdirected request	422 Unprocessable entity	423 Locked	424 Failed dependency
426 Upgrade required	428 Precondition required	429 Too many requests	431 Request header fields too large	444 Connection: close
451 Unavailable for legal reasons	499 Client closed request	501 Not implemented	503 Service unavailable	505 Http version not supported
506 Variant also negotiates	507 Insufficient storage	508 Loop detected	510 Not extended	511 Network authentication required