I suspect you need a new printhead. Go to this site and enter your serial number and look for the part number of the printhead. Note that I made a guess as I do not know your serial number. I think the printhead is this one but I might be mistaken.
Look here for what to do for printhead error
looks like $130 USD which is about 1/2 the price of a new printer.
I know you cleaned the printhead but I am going to post about cleaning anyway.
This link shows cleaning the 8600 printhead and removal is shown here.
This is another type of printhead cleaning, different from the above.
Cleaning and removing ink is shown below by our "Scullery" team.
An HP original video on how to clean the printheads by our experts. Yes, this can get messy, but it works. If your ink levels are good but you are printing blank pages then this is likely the solution.
Official HP advice on cleaning.
Some printers have a printhead cleaning procedure.
| To clean the printhead on an HP printer, access the printer settings through the HP Smart app, navigate to "Print Quality Tools," and select "Clean Printhead"; this will initiate a cleaning cycle where the printer will automatically run a cleaning process to clear any clogs in the printhead |