oembed youtube video work only when connected

Hello,

I have an issue with the youtube oembed option.
I use it in an page, when i’m connected to the dashboard that’s o, i see the iframe and the player, however on private mode or disconected it doesn’t work.

I tried to deactivate all others plugins (as wp rocket, wordfence or wp hide that i suspected, and all others) but it still doesn’t work.

However if i integrate the official iframe html code of Youtube, it works correctly. So it’s just the oembed functionnality.

Do you know why ?

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