One step that is overlooked when attempting to setup a remote hotfolder or remote save location is the database connection setup. This can be accomplished using Core Configure/Database Connection (see screensnap of a working example). The default state for the Core Service Account may be "checked". Remove the "check" and populate the service account name (most likely the same as the SQL Administator username above) and password. The system will need to be rebooted for the settings to take effect.
The information can also be entered at install/upgrade time (see screen snap).