I have a finger lime grown in a container it is now about 5ft and produced some blossoms that developed into fruit only to fall off.
l would appreciate any clues to as why as it does seem to like where it is growing.
All citrus need extra watering when the fruit is setting but you can also sprinkle some epsom salts onto the soil and water it in.
Both are recommended to help fruit set.
N.B. the older a tree gets the more likely it is to hold fruit - young trees will often produce fruit then drop them when the available nutrients are not sufficient, but as roots grow so more nutrient becomes available.