"Sorry, a problem occurred while processing your request." when using the bang "!expert"

This issue has been happening several times to me recently on several browsers (Arc and Firefox).

I type something in my address bar ending with the bang "!expert" and get an error message:

If I try to reload the page I am still getting an error also.

(Request was in French and I'm using MacOS)

Let me know if you need more details, thanks!

I expected the assistant to answer my question

Just adding that I experience this too, with increasing frequency these last few days.