[Jetpack Subscriptions] Subscriptions not working

Hi

I hope this is the right place for my problem. I’ve installed Jetpack (so far no worries), activated the blog subscription, and put the subscription widget in my blog’s sidebar. You can see it here: https://broennimann.eu/dc-nashville-memphis-new-orleans-newyork/

My problem: WordPress (in the stats) does not show a single subscriber, but I KNOW that some people have subscribed via the sidebar widget, including myself. I got an email and I pressed “confirm subscription”, and it showed up on wordpress… BUT there is not a single subscriber in the system…

any ideas what I could do? or am I doing something wrong?
Thanks you very much.