6A80 is a purge unit error, the purge unit is the cleaning assembly on the right where the printhead parks when shut down. If you can move the carriage out of the corner, use a flashlight and see if there are paper scraps or the like keeping the purge assembly from moving freely.
go print -> properties -> page setup -> print options -> tick Disable the paper source setting of the application software -> hit ok and go back to "main" -> select the paper source that you want and hit ok ok and print
The cartridge is only a tank that holds ink. The printhead is the device that you put it into and probably has a blockage in the magenta head. Open the machine so the carriage moves to the center. remove all the cartridges. TCT How to remove and clean Canon Printhead see the link below. The MX700 may have the locking mechanism at the front of the carriage, so you should move it slightly right and then pull the colour bar forward to release the printhead. carefully remove the printhead. Sit it in a shallow dish/tray of hot water for a few minutes and dry with a paper towel. Put it back in the printer reset the locking bar and cartridges. Try a nozzle check through the tools menu. Yoyu may need to repeat the process if the magenta printhead is badly blocked
Try removing the print head and placing in in a shallow tray of HOT clean water for a few minutes. Then place it on a pad of paper towels to draw ink and water from the print head. Re-install in your printer and run a deep clean cycle. re-test your printer with a nozzle check. If still no ink showing at all, repeat the process. If no success after that, the print head is probably dying. Printheads can be replaced, but it is cheaper to replace the machine.
you have a clogged jet and ink has dried inside i reckon... the only other thing it could be is the message from the logic board (its motherboard) inside printer isnt getting to the print head or print head itself has malfunctioned - i would suggest to fix but it would probably be cheaper to buy a new one but dont give up.... sometimes they do work if you print pages even tho there is no flow and the heat may dislodge blockage if there is one... But heres a video that may help...