Hi Maeve,
I checked the shortcode then I deleted the page where it was used and deleted the entire playlist
Then I builted a brand new playlist, copy/paste the shortcode from the playlist manager into a new page and it’s working fine.
So I suggest everyone to ‘Check for weird characters, symbols or spaces in your playlist title that are generating wrong to the shortcode‘.
Thank you for answer ans I wish you a very nice day over there !
Laurent.
PS : Do you have a documentation about the player for customization ?