Either you have lost your network connection, or the device that you are trying to access is offline or does not exist.
To correct this error
Check power to the device and any cables connecting your computer to the device. If you are trying to access a printer over a network, make sure there is a logical connection between your computer and the printer, for example, a connection associating LPT1 with the network printer ID.
Reconnect to the network and try again.