From my tests in my lab on this today (on Unleashed FW 188.8.131.52.246) you'll need to convert the APs back to standalone FW to allow them to join cloud.
You can make use of the Crossbreeder tool to help with multiple APs: https://github.com/andreacoppini/crossbreeder.
Crossbreeder is a troubleshooting and automating some simple commonly used tasks for Ruckus APs such as factory reset, update firmware etc. It does not rely on any controller. Instead, it runs through a list of IP addresses supplied by the user to contact each AP directly via SSH. This utility is built for windows and macOS platforms.
Hope this helps.
Facing a minor issue here. Since by default, all the APs are set up with 192.168.0.1, Crossbreeder is unable to identify all the APs. So we created a DHCP server in one of the Switches with DHCP option 43. However, the APs are not receiving any IPs from the pool.
Do note, that these some of the APs previously had SZ configs in them, so that could be the reason? (Because when I connect a brand new AP to the network, the DHCP pool releases a new IP without any issues and the AP connects with the SZ).
So my issue now is, how can I factory reset number of APs, which previously had SZ-pushed configs in them? DHCP server is not issuing any new IPs to these. But for new APs it does issue. So DHCP is functioning properly. For some reason, the APs with existing SZ configs don't seem to obtain an IP and therefore I'm unable to use Crossbreeder to factory reset.
@rajivw do you know if these APs has static IP assigned or from DHCP?
Try to SSH into one of them and check the IP config.
get ipaddr wan
Also it is worth checking if APs are on management VLAN from old configuration. If yes, APs are tagged with management VLAN, so will not be able to communicate with DHCP server on untagged/native VLAN.