third_party_invite_acceptance_missing· reason_code· applies to service_call, auth_decisionSub-reason for failed_precondition when ak.open.third_party_invite.command.activate.v1 has no usable Station acceptance attestation for the named invite: the attestation signature does not verify against the attesting Station service identity, its audience or verification_id is not this service, or it does not attest a pending ak.invite.third_party on an accepted basis. A caller-reported invite id, a caller-computed invite digest, an Event signature or an HTTP success MUST NOT be accepted in its place. See zh/sync/third-party-invites.md section 7.5.