If not having the right credentials were the issue, they would not have wasted their time or yours to begin with. It has to be another reason. Companies usual

If not having the right credentials were the issue, they would not have wasted their time or yours to begin with. It has to be another reason. Companies usually don't provide feedback for several reasons. One is they don't want word to get out on what the correct answers are to questions - people will game the system. The other is legal protection. They don't want to open themselves up to a lawsuit from someone who thought might have done well in some areas, but not well in others.