Base on the given answer, guessing the issue are related to the network configuration issue more than the Captive portal issue.
Please provide the below info for us to investigate:
Internet <—> Balance One LAN (1) <----> (2) Switch (3)<—> (4) APs
(1)
- How many VLANs defined for the Balance One LAN ?
- Guest/Public Network is under which VLAN ?
- What is the port settings defined for the Balance One LAN interface that connected to the Gigabit switch ? (Port access/Trunk)
(2)
- How many VLANs defined for the switch ?
- What is the port settings defined for the Switch interface that connected to the Balance One ? (Port access/Trunk)
(3)
- What is the port settings defined for the Switch interface that connected to the APs ? (Port access/Trunk)
(4)
- How many SSIDs defined for APs and what is the VLAN ID for each SSID ?
To isolate any configuration issue for the Gigabit switch, do you try before connecting the APs direct to the Balance One ?