You should ask your interviewers after-the-denial, explaining that you would like to understand what they would like to have seen so you can continue to prep/gr

You should ask your interviewers after-the-denial, explaining that you would like to understand what they would like to have seen so you can continue to prep/grow. At worst, it'll be slightly awkward (doing this via email can help mitigate that) and/or they may ignore your request. At best, they may be impressed by your grace and interest in growth (never know how things will play out--you may be their second choice and hear from them again some day). But, really you just want honest answers and most would understand that (as most can relate to your situation). As an interviewer, I'd be more than happy to explain if anyone asked me. But, now that I think of it, I don't believe anyone ever has.