“Not Live” Fallback Content doesn’t work

Hi! We used the “Embed live stream” shortcode to insert the live video into our page https://www.romeoantichita.it/romeo-antichita-in-streaming/

In the area “Use “Not Live” Fallback Content For Live Streams:”, we clicked on the checkbox “Turn on for channel live streams” and we inserted a simple text message in textarea below.

But the message never appears and in its place remains the unavailable video.

We also tried turning on the voice “Turno on for direct link live streams” but nothing changed

The Youtube API have no restrictions.

Thanks!

The page I need help with: [log in to see the link]