Looking at the birth chart of your daughter, her lagan is Scorpio and Rashi is Virgo. She is born under the Uttara Phalguni Nakshtra. Venus rules the 7th house of marriage and Venus is in the 8th house which is not good position for it to be and also Venus is retrograde and in Rahu nakshatra. The possibility of intercast or outside caste is very much there in the horoscope. Also when 7th lord is retrograde, the person is very fussy about the life partner and does not marry easily.