EC2 SSH: Permissions are too open error.

If you’re trying to connect to your EC2 instance via SSH command and you get this error, its because the file permissions aren’t readable only by you. Keys need to be only readable by you. To make this sure (change file permissions), run the following command:

chmod 400 path_to_the_pem_file

Now trying connect the instance again via SSH. The error will disappear.