After rebuilding a new server in the lab, it looks like there was some corruption with the config files that it was using for iptables. The services is starting and the port is listening as expected on 6.6.8.
$ nmap 172.16.55.47 -Pn -p 5432
PORT STATE SERVICE
5432/tcp open postgresql
After going back and carefully reviewing services when server was booting, it was clear that cpass-firewall was failing after succesfully loading firewall rules with iptables.
Active Firewall Rules from iptables can also be found by collecting clearpass logs and selecting System Logs. After extracting the logs, you can navigate to SystemLogs => network-info.txt and scroll down the page until you see "Iptables rule:"
I have listed a snipit for just 5432/tcp from the netwrok-info.txt log file of a correctly working filter. If you dont see the lines for dpt:5432 listed in the input rules, you may be affected by corruption of iptables as well.
Table: filter
Chain INPUT (policy DROP)
num target prot opt source destination
...
...
16 tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5432
...
...
30 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:5432
...
...
You can also open up the SystemLogs => service-info.txt file and see which services have been started by the opperating system. You dont see the cpass-firewall as displayed form the console screenshots, although you will see tcp/udp ports listed which should reflect the network-info.txt log file.