ATP:N System Health shows as critical with message "Device is encountering persistent connection failures"
Verifying this with status_check following can be observed:
Connectivity to Servers:
[...]
AzTec Server is NOT reachable. (https://register.brightmail.com)
Software Update Server is NOT reachable. (https://swupdate.brightmail.com)
[...]
Verifying connection to any of the servers above via tcp_check, connection is shown as "Connected".
It is possible that Symantec Advanced Threat Protection:Network (SATP:N) is connecting via HTTPS/SSL filtering device (Firewall, Proxy Server etc) to the remote systems. If so, filtering of HTTPS connections from SATP:N system must be disabled on these devices.
Please note: It is recommended not to filter any ports or protocols as far as connections from SATP:N device to remote backend servers are concerned.
Please contact Symantec support for further assistance.