This read-only object reports the specific error code contained in the most recent TEK Invalid message this TEK service received from the master, defaulting to noInformation(0) at bootup before any such message arrives. It gives the admin a specific reason, drawn from the same error-code set used for authorization rejections, for why a traffic-key request was refused. For example, an admin seeing this code report invalidKeySequence would know the TEK request itself carried a mismatched key sequence number, distinct from an authorization-level rejection.