Have you also looked at the SNMP reference guide - https://ruckus-support.s3.amazonaws.com/private/documents/1079/Scg200VszhSNMPGuide20160711_final.pdf... . If this doesn't assist you, open a support case.
Are the AP's in the same subnet as Controller? Is the new GW/FW IP Subnet routable with existing Wireless mgmt subnet? If the AP's are routed with a different subnet in between the controller subnet, you'll need to use domain-name ID 15 in your DHCP ...
