In basketball, shooting is a very important skills in all your games in order to be able to get a reliable three-point shot.
In order to have a good shooting skill it is advisable to learn them from the start even though it takes time and also countless of hours practicing. Before practicing for your shooting skills, ensure to also check your accuracy in other basketball skills.
The reason why you are having a hard time to get a reliable three point shot is that it is either you are doing it the wrong way without a coach to guide you on the basic principle and strategies or you are not spending a enough time to practice on your own after been coached.
There are many correct answers to this question. It is difficult to confidently say what the issue is without seeing the player in action. It could be something that could be resolved by practice. One reason could be height.
The player could be too short or too tall to succeed in the jump shot effectively. Another reason is that a player could have an issue with jumping and releasing the ball at the same time. Jumping and releasing must be done at the same time, and for some people, it is difficult to do those two things at the same time.