I just bought a Zebra® ZXP Series 7 and ordered its ribbons true colors card printer ribbons YMCKO 250, 800077-740 AS per your specifications but after installation it gives 5002 error - invalid ribbon. Why? and I have followed all your instructions.
This is an issue that has been seen before on the ZXP7 and ZXP8 printers. There's an article on that error here that lists a few potential causes. The first is that the ribbon may be installed incorrectly. Please double check it's installation using this guide. The second potential cause is that the RFID chip on the ribbon is damaged. To see if this is the case, try replacing the ribbon with a new one and see if you receive the same error.