Answer by Geo for Why do I get permission denied every time I try to ssh from an amazon ec2 server to another linux host?

Ok. Sorry to bother everyone. I found the issue of my situation. In my EC2 server, under the /root/.ssh/ directory is a file called config.

This file had the following settings:

StrictHostKeyChecking no
CheckHostIP no

PasswordAuthentication no

I change the PasswordAuthentication from no to yes.

And that fixed the situation. I hope this helps other people.