canon mp 750 sais “wrong cartgide” I have tried everything. Help me please

I have a canon 3 in 1 “Pixma Mp 750”
tHE ORANGE ALARM BUTTON IS FLASHING AND IT GIVES ME THE MESSAGE “WRONG CARTRIDGE”
i HAVE TRIED THE FOLLOWING:

SWITCHED THE PRINTER ON AND OFF.
PULLED OUT THE CORD.
BOUGHT A SET OF NEW CARTRIDGES (AND REPLACED THE OLD ONES WITH THEM)
CLEANED THE HEADS WITH “JET-TEC” CLEANSING FLUID.

All to no avail. It still gives me the same alarm and message. Has anyone got a notion of what it is??