I have two blueberry plants. Both look healthy and growing rapidly. The one is sprouting delicious blueberries every day. Although the other plant has many sprouted berries, they are green and not ripening. The plants are side by side with plenty of light.
Blueberries need full sun for fruit to ripen, even as much as 12 hours of sunlight is great for producing and ripening good Blueberries.
Refresh yourself on the care requirements in the links below and if you continue to have issues with your plants, a soil test will help you determine if soil nutrients are needed.