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
Preparing the FLY V.3 tanks
Preparing the MBOX V.2 tanks
Never rise the external tank higher than your printer (even temporarily)!