message comes up when you try to print that one or other cartridge is faulty or low on ink and to replace it.ink status monitors are showing plenty of ink though . have replaced both cartridges with new but still same problem
Unfortunately not all compatibles are created equally, some brands work better than others. You can try Woodchip's suggestion by carefully cleaning the cartridges connectors. Use some cleaning fluid (isopropyl acholol) if you have some or gently go over the gold contacts with an eraser. The only real way you will be able to tell if it is a printer or a cartridge fault is to put in a new set of HP branded cartridges and see if you still get the same error.
Incidentally you didn't say if you are still able to print OK despite the error message. Do the cartridges print OK even though the Status Monitor says that they are faulty?