The Remote Print Manager requires there to be another Remote Print Manager running on the Host in order to send a print job to that Host. If no user is logged into the remote Host, then there is no Remote Print Manager running on the Host, and your local Remote Print Manager cannot print to that Host. The Host is said to be an invalid remote printing target, even though you may have an open remote printing connection to the Host (the status in the Remote Printing tab in the Master Connection Window will report that you are connected).
If you create a remote printing job while you are in this state, your local Remote Print Manager will display a dialog explaining that there are no valid targets, but you will have the option to save the print job file to a folder of your choice. See the next section to find out why you might want to save the file and how to send a saved print job file to a remote printing target without going through the print process all over again.
NOTE: Downloading and running PROXY Pro Host on Demand by itself does not install the PROXY Pro Remote Print Manager or XPS printer driver. A Host of this type will not accept remote printing connections and will not even show up as an invalid target. However, if PROXY Pro remote printing is separately installed beforehand on the machine which will run Host on Demand, then that Host can accept remote printing connections and serve as a valid remote printing target.