In CloudSOC -> Dashboard -> Monitoring Dashboard, it shows Securlets and the Connection Status. If the Status goes to Disconnected, an alert should be sent to Admins that are members of the access profiles that have rights to the Monitoring Dashboard and the Securlet. The alert emails are not being sent.
The alerts are currently disabled while utilization is assessed.
Contact Symantec CloudSOC support to ask that alerts be turned on for your tenant.