What causes peaches not to ripen?

Question

Fruit dries up but stays on branches.

Answer 1

Did your fruit develop brown spots before mummifying (drying up)? If so, I think your tree might have brown rot fungus - this causes peaches to mummify on the tree.

You can read more about brown rot fungus, and the recommended course of treatment, at the following link:
https://www.gardeningknowhow.com/edible/fruits/peach/common-peach-diseases.htm