I would ensure that the email addresses you pre-assigned them with matches exactly their registration email addresses, and, if they are authenticated users, the email addresses they are signed into Zoom with - if any.
I would also ensure they are all using their unique join links - and no one is using a generic link.
I would then also ensure that you, and they, are all up-to-date with the latest version of Zoom.
https://support.zoom.us/hc/en-us/articles/201362233-Upgrade-update-to-the-latest-version
Then also try assigning a Co-Host in the Main Room to see if they are able to move stray participants to breakout rooms, if this is still a problem.
Hope this helps.
Rupert
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.
