The problem
When I download the .pem file to ssh my AWS instance, I encountered the following error:
WARNING: UNPROTECTED PRIVATE KEY FILE!
Permissions 0640 for ‘blog.pem’ are too open. It is required that your private key files are NOT accessible by others. This private key will be ignored. bad permissions: ignore key: blog.pem Permission denied (publickey).
The Solution
Run this command in your terminal
ssh -i xxx.pem root@52.74.3.53
Replace xxx.pem with your .pem file name
This will change the keys to be only readable by you.