Technical Tip: Local Captive portal Bridge mode SSID

Local/Internal Captive portal for Bridge mode SSID is not supported; the following option will be greyed out:

Use the tunnel mode SSID to configure the local/internal captive portal.

Bridge mode SSID only supports the external captive portal. Refer to this article:

Technical Tip: How to configure FortiGate Guest Wi-Fi Network using HPE Aruba ClearPass as external captive portal on Bridge mode SSID

Collect the output of the logs below on FortiAP if the user is failing:

cw_debug app fapportal 8
fapportal_diag -d sta

diagnose firewall auth list
diagnose wireless-controller wlac -d sta online | grep <sta_mac>

Related article:

Troubleshooting Tip: Captive portal for local bridge mode SSID when 2nd FortiGate is used as Portal