Nothing can be more dreadful than experiencing HP Printer offline error issue. When you attempt to print an important document, a notification unwantedly pops up that 
is saying your HP Printer is offline. However, this can usually be caused if:

The driver is out of date

The ‘Use Print Offline’ option is enabled.

 Printer has connection issues.

In order to instantly bring your printer online back, you need to navigate to 123.hp.com/setup. The one-stop resolution guide will be at your fingertips. Additionally, 
you are recommended to perform the below-given fixing tips:

Troubleshoot print and network connection issues.

Uncheck ‘Use Offline Printer’

Set your HP Printer as the Default Printer.