Diagnosis
The printer's page count since last cartridge reset has hit a non-resettable threshold, or the toner cartridge chip has failed/been dislodged during refill.
How to Fix It
First, reseat the cartridge. Power off, open front door, remove the black cartridge, and reinsert it firmly. Power on. If error persists, you need to reset the cartridge counter via the printer's service menu. With printer on, from the home screen, quickly tap: Back, Back, Back, OK. Navigate to "Service Menu" > "Reset Supplies" > "Toner Cartridge." Confirm.
If That Didn't Work
The physical chip on the cartridge may be damaged or dirty. Inspect the gold contacts on the cartridge and the corresponding pins inside the printer. Clean both with a dry cotton swab.
Heads Up
Using non-HP toner can cause this, but also premature wear on the drum. The error will return predictably after every ~5,000-page cartridge cycle, requiring another reset.