Webinar Attendanee Report Email addresses not pulling through

Hoping someone might have some answers or help 🙂

I have setup the "Requiring authentication to join a meeting/webinar" within the 'Security' step plus in the individual webinar link, so that the report will include email address of the attendees. But I have pulled the report this morning and the attendee emails haven't been provided???? Any idea how to resolve this?

Thanks in advance