Unsubscribe and manage subscription links broken

Hi,

I installed this plugin and it looks MUCH better than the Subscribe To Comments plugin.

However I have a problem with the confirm, unsubscribe and manage subscription links. When I click on them they redirect me to a blank white page.

I tried to disable W3 Cache plugin and activated the default twenty eleven theme. But the results is a 404 page.

The link that I received in the email is https://furlongdesign.com/comment-subscriptions?sre=barnabas%40barnabasnagy.net&srk=c34bd18b0665796b3748ae86b13185e3&srp=2830&sra=c

When I click on it the following URL is displayed in the address bar:
https://furlongdesign.com/https://furlongdesign.com/?page_id=9999999/

What could be the problem?

https://www.ads-software.com/extend/plugins/subscribe-to-comments-reloaded/