It's Always IAM
There's a phrase that's often from technical circles: whatever the problem is, it's always DNS. Working with a lot of AWS lately, I find another acronym that is taking the place of DNS.
Whatever the problem is, there's a good chance that Identity & Account Management could be the issue. It's a paradigm shift I've had to make from past experience.
Reminds me of what Scott Piper mentioned in his AWS CTF FlAWS:
Through a series of levels you'll learn about common mistakes and gotchas when using Amazon Web Services (AWS). There are no SQL injection, XSS, buffer overflows, or many of the other vulnerabilities you might have seen before. As much as possible, these are AWS specific issues.