Webinar in iframe give "User email is required. (300)"

Description
After creating a webinar and going live, it is being embedded in an iframe

<iframe src="https://zoom.us/wc/700079576/join?prefer=1&un=IElUIEhlbHBkZXNr" width="1000" height="500" sandbox="allow-same-origin allow-forms allow-scripts" allow="microphone; camera"></iframe>

And in the webinar settings registration is disabled.

Error
“User email is required. (300)”

Screenshots (If applicable)

Hey @bader, thanks for posting and using Zoom!

Please see my post here:

Thanks,
Tommy