Chosen Solution
It said “printer failure,” but I don’t know what happened that caused it. It said, Printer Failure There is a problem with the printer or ink system. Turn printer off, then on. If problem persists, contact HP. Then I took pictures:
Sure looks fine internally. Have you tried the troubleshooting steps on HP’s support site? My gut tells me there might be paper stuck in the duplexer. I’ve had that same model printer and it seemed like it was getting choked with paper constantly.