First thing to do is run a nozzle check to see that all ink cartridges are printing. I suspect that you will see that the magenta cartridge is not. Then you should run a head cleaning and even a deep cleaning.
John Hoffman Conway, NH
1D X Mark III, Many lenses, Pixma PRO-100, MX472, LR Classic
After doing the steps above, I noticed the Magenta cartridge wasn't printing, after running a head cleaning, it showed no sign of Magenta, so I continued with the deep cleaning and now the yellow and magenta aren't printing. What should I do now?