The ______ in the error messages will be filled in with the URL you tried to access, e.g. studio.bluebeam.com.
Solution
You’ll see this message if you try to join a Studio Session or Project that is not hosted on a server on your Studio Server whitelist. If you would like to join this Session or Project, please contact your IT department and have them add it to the Studio whitelist.
Studio Enterprise users: to implement a Studio whitelist on your site, please follow these steps.