Unsubscribe link / Manage Subscription page not working

My unsubscribe link and my manage subscription link take me to a “Newsletter signup form”. There is only a contact form to sign up to a newsletter subscription, but are no settings on that page for managing subscription. What is the issue here? I checked the profile page, but it seems totally ok. Why is my unsubscribe link not shown on the profile page? What am I doing wrong? Any ideas?

Thanks,
Cheers!

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