How to use team selective sync
Sharing permissions work in combination with team sharing options that the admin of your Dropbox Business team can set. Team sharing options apply to the permissions for shared links, shared folders, and Paper docs. If your admin enables these options, some actions may no longer be available to you.
For example: your team admin choses not to allow team members to share folders outside of the team. You can't share a folder with somebody outside the team, even if you're the shared folder owner or an editor.
Check with your admin about what's allowed on your team.