There can be multiple reasons for the same. Two main factors are as below:
1. Targeting: You might be reaching out to a generic audience. Facebook offers plethora of options to precisely target your user segments. Its no more the generic targeting based on location, age and gender; there are tons of such parameters available now.
2. Communication: For an ad to perform; communication is the key. Despite of precise targeting your adverts campaign can miserably fail, if you don’t know the targeting well.

There are so many reason when we never receive any lead and query from fb ads
1 targeting
2. age
3. Banner
4. bid amount
5. low audience targeting

watch details video on this How to make FB ADS