mobile_transfer_destination_delivery_unavailable
Transfer-destination verification delivery is unavailable - this deployment has no platform SMS sender.
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/mobile_transfer_destination_delivery_unavailable",
"title": "…",
"status": 503,
"detail": "…",
"instance": "/v1/…"
}