HTTP 428 Precondition Required Error - Meaning & Fix

The HTTP 428 Precondition Required status indicates a missing precondition header in your request. This typically involves headers like If-Match that help manage data consistency. Ensure all required headers are included to meet server conditions.

Main causes

Missing If-Match or If-Unmodified-Since header in the request.
Incorrect or outdated ETag in If-Match header.
Failure to include a required version identifier in the request headers.
Request headers lacking timestamp or sequence information required for conditional requests.

# Request example 
curl -X PUT https://sandbox.oxylabs.io/ -H 'Accept: text/html' -H 'Accept-Encoding: compress' -H 'User-Agent: Chrome/91.0.4472.124'

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Common fixes

Verify the status of the resource and ensure it is not locked by another process or user.
Check the server's configuration settings to ensure that access permissions and resource locks are correctly set.
Contact the administrator to unlock the resource if you do not have the necessary permissions.
Review and resolve any conflicts or dependencies that might be causing the resource to be locked.

# Response example 
HTTP/1.1 428 Precondition Required
Content-Type: text/html
Content-Length: 49

428 Precondition 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