Occasionally one cart can not have a tight connection between the chip and printer's chip sensor, which can cause all carts to read "no cart".
Please unlock all 9 carts, then push them all back in snugly, while watching the printer's LCD panel. When the LCD says "cartridge door open, close door" is when it sees all the cartridge chips, and it's ok to close the door (but, if it says "no cart" or a similar message, then it's not time to close the door). On a rare occurrence, when one cartridge chip doesn't have a tight connection with the chip sensor, adding a thin wedge of paper under the cart makes a good connection for consistent/good read. To do this, take a piece of regular typing paper, about 3x4", and fold it in 1/2 twice so you have a 3x1" folded strip. tape the paper wedge to the bottom of the cart, and insert the cartridge into the printer so it locks into place.
Please let me know your results or if you have any questions.