User does not exits:
The email address is not registered as organizer on Eventbrite
No events found for this user are available at this time:
The user has no live events or the event has ended.
The selected event's attendee list is not configured for public visibility.
You need to edit your event and make sure under "ADDITIONAL OPTIONS",the "Show attendee list on the registration page" is enabled and the First and Last name should be checked.