Hello Mimi,
I would make sure the part number on the new cartridge matches the part number on the old cartridge that was previously working in the device. Sometimes you can purchase a cartridge and it be a metered cartridge and you have a non metered device. Also, you need to purchase a cartridge that is for your region as they can also be region coded.
When I replace the toner, the machine WorkCenter 3335 does not recognize it, even though the toner is correct