Ouch, automatic locale detection, and badly in need of a (proper) translator (for at least Dutch). And no way to switch language that I can find (wouldn't be the first time that was translated with "").
Huh ? You can change the language (I'm in France and I have my theoldreader in English).
You just need to click on your login at the top right and go to "Settings" (probably Instellingen in Dutch).
I'm currently using https://blogtrottr.com to get e-mail updates for RSS/Atom feeds.