Restart your device
Turn off your computer and printer. Then, turn them on again after 2 or 3 minutes. Sometimes, you can fix the internal error by turning off and on your printer.
Check whether your printer is properly plugged-in with your PC or not. There must be no broken cables or loose wires as they are the most common reasons behind wireless printer offline error occurrence.
Log in to your PC
You can log into your PC using an Administrator account and the account liable for the management of printer settings.
Printer Spooler Window
From the start menu, select the Device and Printer option and after that Spooler Window will appear on your screen.