Amazon System Development Engineer interview questions

1st stage phone screening: +1h of technically oriented interview with shared coding/text space on colabedit 2nd stage onsite: a whole day of in depth interviews with multiple employees, mainly engineers

I was interviewed by Amazon RDS Team from Sydney, Australia. I was invited to a Technical phone interview with one of the team members. It was fairly technical and touched in different aspects including TCP/IP stack, networking, Linux internals and commands and a moderately difficult algorithmic question. Also there were few behavioural questions right at the start. All went well in this 40-45 min interview and I think I did pretty well on all the questions (I can say when I don't do well, after working 10+ years and having been interviewed at Google and Microsoft, just to name a few). To my surprise I got a standard rejection email, a day later, saying: "While you bring relevant experience and passion for the role, however, after thoughtful consideration, the hiring team has decided not to pursue with your candidature at this time." . As I was surprised about the decision, so I asked to provide a brief feedback on what went wrong, but my recruiter stopped responding to my emails. Thats weird and felt bad as I believe that having a feedback is a basic right of every interviewee, as it opens up door for self improvement.