Public WIFI + Captive Portal Disclaimer only + only shown after browsing internal network

Hello,

I have a public WIFI network set up with a captive portal set to disclaimer only. Right now, when someone logs onto the public WIFI network, they are not being shown the captive portal. They are able to access the Internet (send and receive HTTP requests).

The only way I've been able to display the captive portal is to browse to an internal address (for example: 192.168.10.16).

Any ideas on how I can make the captive portal display for people as soon as they connect to the public WIFI (this is how it used to work, and I must have messed up a setting).