Please try the following to see if you can resolve your issue:

1.  Open the cover of the printer.

2.  Remove all ink tanks from the printer.

3.  Lift up the gray locking lever on the side of the ink tank holder.

4.  Gently remove the print head from the carriage unit.

5.  Place the print head back in and lock the lever down.

6.  Place all of the ink tanks back in the printer.

7.  Close the cover and turn the printer off.

8.  Unplug the power from the printer.  Leave the power unplugged for about 5-10 minutes.