Paired bid request could not be read
Cross-validation was asked for, but the paired bid request does not parse or is not an object.
What it means
You asked for request/response cross-validation, but the bid request supplied as context does not parse as JSON or is not a JSON object, so none of the pair checks (impid, mtype, seat, deal, currency) can run. The response was still validated on its own.
Why it matters
Cross-validation is only as good as the request it checks against. Rather than skip silently and let a green result imply the pair checks passed, the unusable request is reported explicitly.
How to fix it
Supply the originating bid request as a single valid JSON object (CLI: --request request.json). In batch mode the same request pairs against many response lines.
Example that trips it
{ "id": "req-1", "imp": [ The response may be perfect. The request supplied for cross-validation is truncated, so none of the cross-document checks can run and the validator says so rather than reporting a clean pass.
Check your payload
Paste a bid request or response into the tester to see whether this code fires against it, or gate on the id in CI with the CLI: the id is stable, wording is not.
Back to the full diagnostic code reference.