I'm just copy pasting from other thread but 99% trailing cable.
Open the window and reach up towards the top panel, under that you will have the trailing pack with ink tubes and cables. Lift that down (it's in a U shaped channel), open it a little bit and inspect the trailing cable (fat data cable) for any damage. If you can see the wires from inside inside, it's broken and it needs to be replaced.
2ET72-67020 Trailing Cable