There may be a situation after replacing the service ink container in your machine that the error isn't cleared. This can be due to the reset button being missed when replacing or the users not being entirely sure of the interface of the printer.
You will run into this specific error, "The service ink container in the duplex module is full. At some point, ink smears on your printouts may occur. Obtain a replacement duplex module from HP to avoid ink smears. Use care when removing the duplex module to avoid touching the ink in the container area and any that may be on the roller or nearby surfaces." Please follow the steps below to have this one cleared.
1. Open the Support Menu by pressing the Back button four times.
2. Please select the Support Menu as shown below.
3. Scroll to System Configuration Menu, and then touch the OK button.
4. Scroll to Service ink container Or Duplex module, and then touch the OK button.
5. Scroll to Replace duplex module, and then touch the OK button and you will see the below screen, to select Yes, press OK and the counter will now be reset.