Can a marriage fail due to a parent's disapproval? Has a Prophetic Hadith been reported confirming this? And is a parent's approval an essential condition for marriage?

You must repent from the forbidden relationship with the young man. Marriage is not valid without the consent of the father, who is the guardian. It is forbidden for the father to prevent his daughter from marrying an eligible suitor. If he does so, she may take her case to the Sharia court. It is not an act of disobedience for a girl to take her case to court when her father prevents her from marrying, nor is it obligatory to obey parents if they prevent marriage without a valid reason. The father usually does not refuse except for a legitimate interest, so do not disregard his opinion and try to persuade him, seek mediation from relatives, and seek help from Allah. There is no hadith indicating that marriage fails without the parents' consent, but disobeying them for a valid reason is an act of disobedience and may lead to failure, as sins bring calamities.