Google Translate and Translate this page

When I first used Google Translate, I’m almost certain that it worked as expected for in-page translation of, it’s the page that I tested before writing this:

Now I see, there’s an integral feature – Translate this page – however it’s not working for me. A click on the button is recognised – the button darkens – but then nothing happens, no translation:

Similarly, the Google Translate extension does not have (or no longer has) the required effect.