Assuming your shooting your fletched filed points to center of that target then your arrow is too stiff and your nock is to high or to low and your arrow is bouncing off your shelf and shooting low. If your not shooting field point arrows, start doing that as part of your broadhead tuning.
Knowing your bow type, center cut, and weight at your draw length will help. Some pic's of your form would be good to see if you have the correct draw length. Bad form weighs heavy on all other factors.