numbers_carrier_failed
HTTP 502§9.17 The customer team workspace on the phone (`/v1/mobile/workspace/*`, `/v1/mobile/voice/token`)
Twilio did not answer or did not complete the step (search, caller-ID call, bill upload, cancellation, trust registration). Nothing was assumed; retry.
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/numbers_carrier_failed",
"title": "…",
"status": 502,
"detail": "…",
"instance": "/v1/…"
}