My printer works in first week, but now cannot print.
1- Make sure that the air vents are installed on the outer ink tanks of the CIS. Run a head clean and a nozzle check. If still not printing, wait an hour and run another head clean.
Running multiple head cleans in a row is counter?productive and will actually make the print worse. After head clean, leave printer on overnight for best results.
2-This happens, if you forget open the small plugs (travel plugs) of the tanks.
Preparing the ROBUST V.4 tanks
Warning :
Never rise the external tank higher than your printer (even temporarily)!