Unable to activate Developer Mode on Meta Quest 3S

Hello, I need help.

I want to activate Developer Mode on the Meta Quest 3S: I have a verified account with a card linked to it.

However, when I try to activate via the Meta Horizon app, it shows "Errore Imprevisto / Unexpected Error". Does somebody know how fix that?

I've tried the Meta Quest Developer Hub on Windows too, but it doesn't open, it shows a gray background without nothing.

Thanks!