stripe_subscription_missing
The tenant has a local subscription but it has no Stripe subscription id (for example, a dev-seeded or externally provisioned row). Stripe customer-portal cancellation and plan-change deep links refuse rather than guessing which Stripe subscription to mutate.
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/stripe_subscription_missing",
"title": "…",
"status": 409,
"detail": "…",
"instance": "/v1/…"
}