Safari not supporting end-to-end encryption for Facebook video and audio calls

On Facebook I'm unable to make outgoing video or audio calls because the buttons are grayed out, and when I receive a call I get an error message that says "Use a browser that supports end-to-end encryption on Messenger and Facebook" and has a link to a page that says that Safari is allegedly a supported browser. I've updated to the latest OSX and the latest Safari versions but no change in the behavior.

[Re-Titled by Moderator]

Original Title: Facebook End-to-end Encryption issue