CAS device is running version prior to 3.1.4.1.
When do a "Test Syslog" under Settings > Alert Locations, packet capture shows no syslog traffic been sent out.
However when the CAS device was restarted, doing the same test, packet capture shows syslog traffic been sent out but subsequent test fails.
The server setting is using a hostname and also an IP.
Release : 3.1.2.4
Component : Syslog
This is a bug affecting version prior to 3.1.4.1.
Upgraded to 3.1.4.1 and it resolved the issue.