You'd check whether there is any Netflow data from the controller to Purview.
I've got that from here...
https://gtacknowledge.extremenetworks.com/articles/Q_A/Wants-somebody-to-review-his-Purview-config-t...
!!! The controller uses port 2095 instead of port 2055 !!!
So to check for Netflow data ssh to Purview.
Do a "ifconfig" to see the interfaces - I assume that you use eth0 for the 172.16.0.138 interface so the command is....
root@purview:/$ tcpdump -i eth0 udp port 2095
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
23:38:07.681163 IP 10.12.0.1.2095 > purview.wywlan.com.2095: UDP, length 84
23:38:16.045706 IP 10.12.0.1.2095 > purview.wywlan.com.2095: UDP, length 1450
23:38:16.780486 IP 10.12.0.1.2095 > purview.wywlan.com.2095: UDP, length 1450
23:38:17.194480 IP 10.12.0.1.2095 > purview.wywlan.com.2095: UDP, length 1450
^C
I've done the command and connected with my WLAN client and opened some webpages to get some Netflow data.
Also please doublecheck if you've configured it like this....
https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-configure-Identifi-Wireless-Control...