I managed to solve this by changing the login destination on the App sign-in page from the default “unleashed.ruckuswireless.com” to the IP address of one of the APs.
iPad Pro 2019 and iPhone 14 Pro both running iOS 16.3. Neither can access unleashed.ruckus.com. But weirdly the iPhone has never shown the Local Network access in the settings, whereas the iPad does.
