Sharing map permissions issues

In the web version of MindManager Professional, when I share a map for editing with another colleague, when they open the shared link, MindManager returnes a "Insufficient Permissions. You do not have permission to read this file." error message. I have tried sharing files located in OneDrive and Dropbox, with the same result. I get the same error message on maps that my colleague shares with me. I have tried putting the maps into folders that are shared with this colleague; same result.