What is OKI printer offline error? and How to resolve it? from ronni jakson's blog

OKI Printer offline error is one of the most common errors that can occur. There are various reasons that this can occur.

Turn off your printer, and for some time.

Update all the drivers of the printer.

Find if there is any connection problem that occurs in the HP printer unit and the computer system.

Check the ethernet connection to your internet port and make sure it is connected to the network.

For this, go to Start-> Devices and printers. Then, right-click on the HP envy printer and choose the printer from the context menu.

Uncheck the option to use the printer offline. This will resolve your problem, and you turn your HP printer to online status.

To get the permanent solution follow Oki Printer is Offline