In Firefox, enter Options > Privacy & Security > under "Enhanced Tracking Protection" click "Manage Exceptions"
There seems to be no way to add a domain or site to the list of excepted sites (currently the list appears to be empty).
I want to exclude a specific domain from having Tracking blocked (Google reCaptcha is not working and I think this is why). I don't want to just blindly allow all tracking, I want to only allow per site for better security.
I think I found it. In the Firefox address bar click on the Shield icon left of the URL, then click the Toggle for "Enhanced Tracking Protection is ON for this site":