· Press and hold the power button to turn off the printer and turn it back on after a few minutes.
· If the error is still displayed, check the drivers from your PC whether they need an update.
· Use the printer troubleshooter to detect the problem and troubleshoot if found any.
This is how you can fix HP Envy 4520 printer offline error with the above quick technical resolutions. If any help is needed, you can contact our technical member straight away.