If your new URL is not working, could you at the very least share the URL so we can check it for ourselves?
I’m not sure if the page you’re seeing is from our servers or from your domain forwarding service, or whether this page is because cookies are actually not enabled or because of a bug, potentially with your domain forwarding service.
That said, I would not recommend using URL forwarding if you want to put your website on your own domain. You can just host the domain name with us and setup your website directly on your domain name without any redirects, forwards, frames or masks.