Websub.rocks Cannon find subscriber

I tested my site with websub.rocks and it tells me it cannot find anything:

We didn't find a hub or self on your page. Ensure your page has either HTTP Link headers or HTML or XML <link> tags indicating your hub and self URLs. See Discovery for more information.

Is this a known issue or am I doing something wrong?

The page I need help with: [log in to see the link]