Printing Errors or Lights & Stuck Print Jobs

I am getting the error message so many others have gotten, precipitated by nothing except owning for ~3 years. BTW, was sold a refurbished ("HP Certified Reconditioned") from your HP Cust. Svc. (barcode on the back says 9A512) as a new one after the last one had issues.

ERROR: Ink System Failure. There is a problem with your printhead...

I have an

OfficeJet Pro 8600 N911a

Serial [edit]

Prod. No. CM749A

I have trouble shooted for ~2.5 hours (research and trying different methods) and had no success.

I have tried:

"With the printer turned on, disconnect the power cord from the rear of the printer and also unplug the power cord from the wall outlet.

Remove USB cable, if present.

Wait for 2-3 minutes, press and hold the power button on your printer for about 30 seconds to remove any additional charge.

Now plug back the power cable straight to a wall outlet without any surge protector or an extension cord and then plug back the power cord to the printer.

Turn on the printer and wait till warm-up period finishes and the printer is idle."

"Perform a hard reset on the printer and make sure that the printer is connected directly to the wall outlet and not to the surge protector.

With the printer turned on, disconnect the power cord from the rear of the printer and also unplug the power cord from the wall outlet.

Remove USB cable, if present.

Wait for 2-3 minutes, press and hold the power button on your printer for about 30 seconds to remove any additional charge.

Now plug back the power cable straight to a wall outlet without any surge protector or an extension cord and then plug back the power cord to the printer.

Turn on the printer and wait till warm-up period finishes and the printer is idle.

Next thing, I would suggest here is to update the printer firmware, you can do this directly from the printer firmware or you can download the software from hp support website.

If your printer connected wirelessly, make sure to temporary connect the device with USB and then follow the link to install the latest firmware update on your printer, Click here

For more details on how to update the printer firmware - HP Printers - Updating or Upgrading Printer Firmware"

"

1. Unplug all cables and memory cards from the printer.  Unplug the power cord, directly from the back of the printer while the printer is still turned on.
2. Unplug the other end of the cord from the power source.
3. If there is a power module on the power cord, disconnect one end and reconnect it.
4. After 60 seconds, plug the cord directly into a wall outlet ( not a surge protector or battery backup ).
5. Plug the power cord into the back of the printer.
6. The printer should automatically power back up.  If it doesn't, turn it on with the power button.
7. Try making a photocopy (if your printer is an all-in-on printer) before connecting any other cables to the printer.
8. Connect any other needed cables to the printer."

These: https://support.hp.com/us-en/document/c04100778/

Please tell me what I can do besides all the steps that I have already taken.

Thank you