HP Offline troubleshooting can happen or pop up for various reasons concerning your printer access. Try to find such trigger reasons like improper printer connection, outdated or corrupted driver, and more to resolve them to get uninterrupted printing access. For more on HP Printer is offline check the link given.

How to solve HP Printer offline error :
First, use the active system settings- select the Devices & Printers option.
Move on with the list of available printer names shown as per your device. Just right-click on the required HP printer name to select the necessary option via the drop-down menu- See what’s printing.
Now, connect through the Printer tab and try to uncheck the settings options Pause or Use the Printer Offline option.
Further, pick the settings like- Use the printer Online.
Finally, select the document to be printed and start making a test print using a print option to resolve HP Printer is offline issue.