I'm using an AWS AMI from Bitnami "NGinx Certified by Bitnami" and I have installed Webmin successfully as seen in this Gist. Including opening the port 10000 in the firewall. But I still cannot access WebMin at https://publicip:10000 - it just times out. I've rebuilt the server twice and tried with another Bitnami image but get the same result.
I've installed Webmin on other servers many times successfully. Although it's been a couple years.