How do I make my Hp printer offline so it can go back online

To fix the HP printer offline, turn it off and disconnect from the power source. Restart your 

router and the device from which you wish to print. Then turn the printer on and try 

printing. You can also use the HP Smart app to fix the offline printer issue. In this app, use 

the Diagnose & Fix tool for this purpose. Also check the printer and network connections 

and clear the print queue.

Visit:- https://www.hpprintersupportpro.com/blog/stop-my-hp-printer-from-going-offline/