Shared Folder Sync is a network service that allows users to sync shared folders between DiskStations. Starting from DSM 4.1, Shared Folder Sync provides Multiple-Source Shared Folder Sync feature, which allows multiple clients to sync their shared folders to one DiskStation.
However, when a shared folder on the destination is already connected to a source, syncing requests for this shared folder from other sources will be rejected. You can unlink the connection of this shared folder to allow another source to sync with it.
To set up Shared Folder Sync service on the destination side, please go to Main Menu > Control Panel > Network Backup. In the Shared Folder Sync tab, you can do the following: