Captive portal x Fortinet

[PooWa]

Hi there,

I'm experiencing an issue with my infrastructure and would appreciate some help with it.

On the OPNsense side, I'm using FreeRADIUS and a captive portal, and the authentication is working perfectly.

Here's my setup:

I have one access point managed by a Fortinet firewall.
The Fortinet firewall provides DHCP and redirects me to the OPNsense captive portal.
The URL for the redirection is generated by Fortinet with a magic token.
From my research, this seems to be part of Fortinet's walled garden, which prevents internet access until authentication is completed.

The issue arises after authentication. Although I successfully log in and see the logout option, I still don't have internet access.

I suspect that Fortinet needs some sort of acknowledgment, but I'm not sure what steps I need to take or what changes I should make in the captive portal configuration to enable this acknowledgment.

If you need more information to assist me, please don't hesitate to ask.

Many thanks!
Regards,
PooWa