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.