Unfortunately, when you receive the HP printer offline error, you cannot execute the printing jobs. To fix the problem, you need to check for the drivers. If the printer drivers are outdated, update them now. Also, check for connection issues. Make sure that the device has an active network connection. You can run the HP print and scan doctor on the device to fix the printer offline issues. Set your printer as the default printer, and try to print the documents. If an error is still there, do not wait to contact the expert team for help.

https://l-123hp.com/blog/hp-printer-offline/