I failed the iv but the interviewer did not tell me where do i lack off they just straight away give me the result and the second interviewer is kind of not really responsive

The interviewers were friendly and polite, i was briefied with the possible question that will be asked before the interview actually. Besides of receiving these question, I have been asked about my career plans and as well as my previous working experience. Furthermore, I was asked some practical question and I was given actual case scenario and was asked as to how would i deal with those issues