A man falsely accused a woman of having lawful intercourse through mutah but was lying. He was wondering if this constitutes as qazaf one of the 7 major sins of accusing a chaste woman. He has obviously repented for this and told that it was a lie but wants to know if the sin was just lying or if it was this major sin of accusing a chaste woman. He was confused because technically the accusation wasn’t a sin but he knows that the lying was. Is this a major sin mentioned by the prophet?