Remove the affected cartridge from the printer.

The cartridge IC chip is located on top of the cartridge.

Press the pins of the chip resetter on the three contacts of the IC chip until the LED of the resetter turns green.

Re-insert the cartridge into the printer. If the cartridge is still not recognized, try again several times and switch the printer off and on again.

If the problem is not solved, either the cartridge IC chip is defective (in this case, a new cartridge should work) or the problem is located on the printer side (e.g. defective main PCB or damaged software).