If the machine loses network connectivity by itself, you should troubleshoot the issue exactly like when any other network equipment loses connectivity:
- Check the printer from a PC to verify that it actually is offline.
- Check cables.
- Check the settings.
- Check for duplicate IPs on the network.
If window is reporting the printer as offline: If Windows is reporting the printer as offline, it is just saying that it receives no status updates from the printer. This is a Windows/printer port communication issue and is rarely related to the printer itself.
It is highly recommended that you should either reinstall the driver or go in to the Printer Properties, select Ports and set up a new TCP/IP port with the IP address of the printer.
If the issue is still not resolved, something is likely blocking trafic on port 9100 on your network. This is generally the case if the PC is connected to a wireless network and the printer is on a cabled network. Sometimes it can be fixed using router set up.
If you cannot solve the issue, you can work around it by selecting the newly created TCP/IP port, click the Configure Port button and from there you need to disable the SNMP Status Enable” checkbox. This will cause Windows to no longer attempt to monitor the status of the printer and it should therefore never report the printer as offline.