I confirmed the bug. Not working in Tor. Thanks for reporting.
Tor is blocking mempool space api.
I remember using it before (when you first created it), and it worked fine. I'm pretty sure I used Tor browser back then too.
I am traveling in vacation.
Enjoy your vacation!
Edit: impressive you sre the first user in years that really uses Tor

If I'd be the only Tor user, that wouldn't give me much privacy

I used a normal browser to see the result, that worked.