This counter increments when an authorization response's authenticator or signature fails to validate, which, like the authentication-phase equivalent, almost always traces back to a shared-secret mismatch between switch and server, but caught specifically on authorization exchanges. Because authorization requests fire far more often than authentication requests in an active session, this counter can climb quickly and give an admin an early, high-volume signal of a secret-key problem even if the initial login somehow still succeeded. For example, if every subsequent command triggers an authorization check against the bad key, this counter would spike immediately after login while AccessAccepts on this same table stays low.