First, the Shared Canvases page is a personal view. It only lists the canvases you published yourself, so teammates will not see your canvases there and you will not see theirs. To view someone else’s canvas, they need to send you its share link.
Second, opening a share link currently works only when the viewer is in the same Cursor team as the publisher. Your organization has several Cursor teams, and a team-visible canvas can only be opened by members of the exact team it was published from. Colleagues in the other teams of your org will see an error for now. This is a known issue we are already tracking, and I have added your report to it.