ENDIAN Firewall - unblock only one site https

Hello and good morning to everyone!
just now I register in this forum. I'm an IT and I've installed and configurated endian Firewall Appliance release 2.4-0, with proxy service.
In outgoing traffic I closed the rules for port 80 and 443. In proxy configuration is setup not trasparent mode for green and blue zone, and in the end I created some access policy for adjust the exception of accesses or denied in some sites, for example: I want forbidden access in facebook, but enable in google.com or live.com. All works fine, but I need to enable one site in https (wetransfer.com), so what can I do? The rules in access policy and content filter dont work correctly, I can access in site wetransfer.com, but when sending a file, the transfer fails.
Please help me.
Thanks a lot in advance.

Fabio.