Received a simple "pre-phone screen" coding challenge which I completed in less than an hour of receiving it. Sent back a response and follow-up before getting a rejection more than a month later with nothing more than "your score did not qualify." To which I sent a response asking for some more clarification on what I was scored on and what I did wrong, as the code I submitted works in it's entirety as per the challenge description (I also included statistical evidence of it's correct performance). Got a response that they would forward it to their engineers, and then was ghosted.