You can mount remote folders from remote servers (such as network computers or other Synology NAS devices) to the File Station on your Synology NAS. This allows you to navigate and manage the mounted folders from your Synology NAS. Click Tools > Mount
In the notification, I see the error "Unable to mount all folders automatically". I looked in the Log Center to try to determine which folder it is referring to.
This guide contains detailed instructions on how to setup Synology NAS DiskStation with WebDav, in order to be able to Map (mount) the NAS Shared drive as a Network drive outside of the local network.
Once you have mounted a shared folder you can transfer files to and from the external server from within DSM. This makes the process of managing files across your environment incredibly easy!