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PQC Session Capacity Reached

URI: https://docs.ankatech.co/errors/pqc-session-capacity
HTTP Status: 503 Service Unavailable

When you see this

The platform has temporarily reached its capacity for new PQC transport sessions, so the PQC handshake (POST /api/v3/pqc-handshake/init) was refused. No key exchange took place and no session was created.

The condition is platform-wide and temporary: capacity frees up on its own as earlier sessions expire. It is not a rate limit applied to your client.

Response Example

{
  "type": "https://docs.ankatech.co/errors/pqc-session-capacity",
  "title": "PQC Session Capacity Reached",
  "status": 503,
  "detail": "The platform holds its maximum number of pending PQC sessions. Retry the handshake after the indicated interval.",
  "instance": "/api/v3/pqc-handshake/init",
  "correlationId": "8d41f0b2-6c3e-4a57-9e21-0b7d5f3a9c64",
  "timestamp": 1760090400
}

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

How to Resolve

  1. Wait the number of seconds in the Retry-After response header, then retry the whole handshake.
  2. Once a handshake succeeds, reuse its session for your requests instead of starting a new handshake per request.

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