Have you actually asked them about the specific reasons for rejection? FWIW, there's a multitude of reasons why one could get rejected, ranging from automated systems to the position just getting filled to being too good for the job to bad references to human error. Until you ask and get an actual human response, you're completely in the dark.
It's a no-reply email. Here's what the actual email said:
"Thank you for your interest in Company. We have reviewed your resume, experience, and responses to the Code Challenge. At this time, we have decided to move forward with other candidates in the process. We wish you success in your job search."
Sounds to me like they read my resume AFTER I passed the coding challenge. Seems to me like a waste of terrible time if I'm spending my time just to get rejected by my resume.