More details would help diagnose possible causes...

1. What is "normal" for your husbandry?

2. What kind of enclosure and what size is it?

3. How long have you had the ball python?

4. How many times has it eaten for you?

5. How often are you trying to feed? How long do you wait between failures to eat?

6. Are you hovering and watching to see if your ball python eats?

And any other details you can think of.

In my experience, juvi ball pythons are typically voracious eaters, so long as they are feeling secure. What you're describing sounds like an issue with security, rather than some sort of "inability" to coil and kill the prey.