We’ve released a new alerting feature for Secondary DNS. The advanced option Email Alert on Disable will send a message to the alert email address configured for your account if a zone is automatically disabled due to a fatal error condition or the SOA EXPIRE is reached (stale zone).
Secondary DNS domains can become disabled under certain fatal error conditions (all of which are described in the help documentation). This new alerting feature defaults to off and can be enabled in the account control center on a per-zone basis.