ZD 1200 running latest 9.10 firmware.
6 x 7372 AP's connected via Cisco SG300-10 PoE switch.
I have tried different IP's on the same LAN.
I have tried putting the ZD in a DMZ and restricted firewall access to it.
Cyberoam CR100iNG firewall.
Juniper EX4400 (x5 in virtual chassis)
If the ZD is not connected to the customers LAN, it works without issue.