Is the ball kicking up to the opposite cannon after you make the first shot? If not then check the diverter under the playfield and then check the opto on the left & right cannons.
I kinda thought the first shot was the NZ and then the second is the scoop, and then back to NZ.
I would also suggest that you go into switch test mode and see if your cannon wiring loom is failing. That’d be my first guess. Jiggle it a bit and if switches start closing then that’s the problem .