Captive portal not forwarding HTTP and HTTPS

[Amr]

Hey guys,
I've been experimenting with captive portal and Transparent proxy and managed to get them to work, but my problem is that I can't get them to work together.

Normally when you have NAT port forwarding rules for HTTP(S) to proxy it'll bypass the Captive portal so I removed the NAT rules and tried to check the Forward HTTP and HTTPS option in CP but it just won't work :c.

also when I check the rules I get locked out of the GUI and I get this message:
Failed to establish a secure connection to 192.168.1.1
The system returned:
(92) Protocol error (TLS code: X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT)
...

any ideas?