are too open. It is required that your private key files are NOT accessible by others. code example
Example 1: it is required that your private key files are not accessible by others
$ sudo chmod 600 /path/to/my/key.pem
Example 2: It is required that your private key files are NOT accessible by others. This private key will be ignored.
sudo ssh ...
Example 3: It is required that your private key files are NOT accessible by others ubuntu
chmod 400 {keyfile}.pem is what amazon instructed and it works.