Carriage jam
Something is physically stopping the cartridge carriage moving across. Switch the printer off first, then open it and look. On a newly unboxed printer the culprit is almost always packing tape or an orange plastic clip nobody removed. On an older one, look for a scrap of paper under the carriage rail, and check the thin clear plastic strip running behind the carriage isn't smeared, because ink on that strip makes the printer lose track of where the head is and it wipes clean with a dry cloth. Move the carriage gently by hand once the power is off to feel where it catches.