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Key-Backend Connection Test Unavailable

URI: https://docs.ankatech.co/errors/key-backend-reachability-busy
HTTP Status: 503 Service Unavailable

When you see this

A key-backend connection test was refused because every reachability permit in this admin-api instance is held by a test already in flight. It is a refusal, not a verdict: nothing was contacted, so the response carries no self-test verdict and no audit row describing one, and a Retry-After header tells you when to try again.

Common Causes

  • Several connection tests are running concurrently across the deployment plane and the tenant planes, and the concurrency bound is exhausted.
  • Every probe worker is occupied by a handshake that has not yet returned, so a new probe cannot be admitted.
  • A backend endpoint validation ran while the probe pool was saturated.

Response Example

{
  "type": "https://docs.ankatech.co/errors/key-backend-reachability-busy",
  "title": "Key-Backend Connection Test Unavailable",
  "status": 503,
  "detail": "Too many key-backend connection tests are already running; retry the operation shortly.",
  "instance": "/api/v3/admin/platform/setup/key-backend/test",
  "timestamp": 1730000000,
  "extensions": {
    "requestId": "ab35d709-6c81-4e27-93f5-1d84a0f7b6ce"
  }
}

Content-Type: application/problem+json — the response follows RFC 9457 Problem Details.

How to Resolve

  1. Wait for the interval named in the Retry-After header and re-run the test.
  2. Do not read this as a statement about the backend — nothing was dialled, so it says nothing about whether the backend is reachable or the credential valid.
  3. If it recurs, stagger concurrent connection tests: the deployment-plane test draws on the full bound, including the permits reserved for the tenant planes.

For full schema definitions, examples, and interactive testing, see the Developer Hub Reference.