Additional sign-in or account-related issues within Microsoft Teams for business
Hi
My name is Daniel. I am an Independent Advisor.
I suspect that's because they joined anonymously. If you are trying to collect emails as leads then the way to go about this issue by setting up the registration page so you would collect the emails upfront before the event has started, not afterward like the attendance report.
Please see the demo video on how to create a registration process for Microsoft Teams live events with Power Automate.
If you are business account users, the Power Automate license already included so please take advantage of the opportunity. https://www.youtube.com/watch?v=Sl_JF4wiqec
DISCLAIMER:
There's a link above from the non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
Kind Regards