Description
This article describes how to troubleshoot and resolve the 403 Forbidden error encountered when accessing a captive portal on a FortiGate firewall configured with FortiAuthenticator as the authentication server.
Scope
FortiAuthenticator.
Solution
User-based policy is setup on the FortiGate firewall for internet access where FortiAuthenticator is used for external captive portal authentication.
The following error may appear when attempting to trigger the captive portal page on a user's machine:
403 Forbidden: You are not allowed to access this resource.
Go to FortiAuthenticator, System -> Network -> Interfaces (select the interface where the captive portal FQDN/IP is mapped to)
Check whether the captive portal service is enabled.
Enable it and verify the captive portal again.
The captive portal page now appears on the user's machine, and upon successful authentication with correct credentials, internet access is granted.
