google_email_unverified
The Google account's own email is unverified, so it cannot key a Vocapable account. Cure is verifying the address with Google, not a different request.
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/google_email_unverified",
"title": "…",
"status": 403,
"detail": "…",
"instance": "/v1/…"
}