I am a site collection administrator. I can embed youtube videos in a page, but I am unable to embed an Excel file from the site Documents (or OneDrive). The error message I receive is:
Embedding content from this website isn't allowed, but your admin can change this setting.
I do not see "HTML Field Security" option in the Site Collection Administration section, which means that scripting is disabled by the organization administrator, but wouldn't that disable embedding completely (even from youtube)?