The user Guide has some datails on thi: " Network resources—displays the number of connected and disconnected Enterprise servers, heartbeat connection status,
and the configuration status of your SMTP server and Policy Manager. To test the heartbeat connection status through port
443 and verify the connectivity to the Enterprise servers, click Test connection.
NOTE: By default, secure connect gateway verifies the heartbeat status every 24 hours."
If the explanation is not sufficient, you can provide feedback by opening the document in https://www.dell.com/support/ <document> and then click on " View page"