This read-only object reports the specific error code the Radio Master most recently sent in a TEK Invalid message for this TEK association, defaulting to noInformation(0) at bootup before any such message has been sent. It gives the admin the precise reason, from the master's side, that a key request on this association was rejected. For example, an admin seeing this code report keyRequestAuthenticationFailure would know the rejected key request failed an authentication check rather than simply arriving out of sequence.