my sour sop produces fruit the size of a palm nut which dies of without maturing

Question

it brings fruits the size of a small palm kernel nut, but the fruit turns black, dry and dies off as soon as possible

Answer 1

Fruit drop can be from several reasons.
Weather, pollination, pests, disease or overbearing.
These links will help you.

https://www.gardeningknowhow.com/edible/fruits/soursop/soursop-tree-care.htm
https://hort.purdue.edu/newcrop/morton/soursop.html