cc_quality_answer_invalid
An answer does not fit its question (N/A where not allowed, a scale value on yes/no, an unknown question).
Problem shape
Every non-2xx response is an RFC 9457 application/problem+json body. The type URI below is stable and machine-matchable, so branch on the final path segment (the code) and treat the status as redundant confirmation. See the error-handling guide.
{
"type": "https://docs.vocapable.com/errors/cc_quality_answer_invalid",
"title": "…",
"status": 422,
"detail": "…",
"instance": "/v1/…"
}