DIAGNOSIS The printer detects a non-HP or previously used toner cartridge that has a full or corrupted memory chip. It is a firmware lockout.
FIX You must replace the triggering cartridge with a new, genuine HP 126A/126X series toner cartridge. 1. Identify which cartridge is causing the error from the status message. 2. Open the front door and remove the indicated cartridge. 3. Install the new genuine HP cartridge. The error should clear immediately.
IF THAT DIDN'T WORK Perform a cold reset to clear the printer's memory. With the printer on, simultaneously press and hold the Cancel and Right Arrow buttons for 5 seconds. This resets the supply counters.
HEADS UP This error is designed to block third-party cartridges. Aftermarket chips rarely fix it permanently; the error will often return.