push_route_limit_exceeded· reason_code· applies to event_envelope, service_callA `ak.device.push_route` registration would exceed the v1 wire limit of 16 active push_route entries per `(recipient_id, principal_id, device_id)`. The server MUST reject the new registration. See zh/crypto-media/device-lifecycle.md §5.6.2 and zh/conformance/scalability-constraints.md §6.1.