Please remove the cartridge, using the Priming tip at the end of your syringe, see if you can pull a prime on the cartridge through the exit valve, as you would have before installing it into the printer. This will tell you if it's the cartridge exit valve that is blocked. If it is not, this leaves the Damper, Print Head OR capping station that is not allowing ink to pass through the ink line for this position. This printer model is a real bear to get into to clean the Capping station and bottom of the print head effectively.
In addition, leaving a printer sitting for an entire year with Pigment inks installed is never a good idea, especially with this printer platform. The heads are intolerable of drying pigments and clog VERY easily, even with regular/frequent use. Once the print head has a clog in the channel it is sometimes very difficult to remove it, even with Piezoflush or Windex due to the design of the channels in the head, as well as the inaccessible capping station and Print head.