I have an AP One and Balance 20 (both on latest firmwares) and my second SSID (guest network) does not work.
I have a Data VLAN and Guest VLAN. The data VLAN on wireless works fine. If I join the guest network that is on the guest VLAN, I cannot pull an IP address and can’t even connect with a static address. If I associate the guest SSID with the data VLAN instead of the guest VLAN, it connects just fine.