on your captop - you have 3 nipples - 2 for the hoses what was on your third one
Excellent - so check your hoses. If you have a blockage (usually T connector) it will blow a hose off and leak ink into the machine. Also good to check the connector as magenta is a known clogger in certain environments. At times you have to snip the hoses to ensure good suction. If you are not getting a color usually air or damper.
Well I could not disagree more, maybe I could. You have perfect nozzles in all but one channel and they say flush the whole system. With the BN20 you have a user level flush that you do not have with the larger machines, so that a good thing because you only need one cleaning cartridge and it will run through all the inks. The tech level and the larger machines need one cart for each channel.
As for white, you do not need it if you are not using it, you can replace white with a cleaning cartridge.
You can also print just that channel and not waste ink on the other colors. No ink, no closed system, air from somewhere, somehow - you a syringe, clamp one hose and pull from the other, if two channels move and not the one you want, then switch lines.
So how were you told to flush it? U cannot properly use the machine with the channel missing, for if it needed it and it is not there you will have banding. With that said, if a complete channel is missing, you first check for air - larger machines you can choke clean, not on the BN, so you need a syringe to pull the air out. If that does not work, or does not hold, then you need to look at the damper. However, if the cyan is missing, then you can in your graphic program make 100% cyan blocks and run that file until the ink comes to the head, that save you from wasting the MYK just to get the C.