DIAGNOSIS The inkjet printhead nozzles are clogged with dried ink. This is the universal plague of inkjet printers, and it hits this model hard because the printhead is built into the cartridges, which can dry out.
FIX Run the printer's built-in printhead cleaning utility. On the printer itself, press the (i) information button to get to the settings menu, navigate to 'Tools', then 'Printer Maintenance', and select 'Clean Printhead'. You can also do this from the HP Smart app under Printer Settings. This will waste a bit of ink. After it runs, print the 'Print Quality Report' from the same menu to check.
IF THAT DIDN'T WORK If software cleaning fails, you need to clean the cartridge contacts and the contacts inside the printer. Power off, remove the cartridges, and use a dry cotton swab to gently wipe the copper-colored contacts on both the cartridges and inside the carriage. Reinstall and try another cleaning cycle.
HEADS UP Don't run the cleaning cycle more than twice in a row—it's a huge ink-waster and can flood the waste pad. If two cycles don't fix it, the cartridge/printhead is likely too dried out and needs replacement. Using the printer at least once a week helps prevent this.