Certified GKH Gardening Expert
Not every cutting will take root. It is just the way it is. But, there are some things that you can do to increase your chances of a cutting rooting. It sounds like you are rooting in water, so with that, change the water about once every 1-2 days. Also, try adding a little rooting hormone to the water (available at most places that sell plants). This will help to stimulate rooting as well.
If these cuttings are already dying, they may be too far gone to root, so you may need to get more cuttings to root.