You don’t state which version of Moneydance you are running.
Assuming it is 2017 then the Network Synchronizer is no longer used. Any reference in the mobile APP is only applicable to older versions of Moneydance. You need to have at least a free Dropbox account. Instructions on how to enable syncing with a Mobile device can be found in the knowledge base article at http://help.infinitekind.com/kb/syncing-and-sharing-data