After setting up SSH etc, ssh key not accepted and can't login.

After creating an SSH key and then creating a droplet (embedding the ssh key), I followed this tutorial on securing the droplet. But it ended up making it so the ssh key was rejected, after which I needed to destroy the droplet and start over.

https://www.digitalocean.com/community/tutorials/initial-server-setup-with-ubuntu-14-04

Step five, where in file /etc/ssh/sshd_config you set PermitRootLogin no made it so the ssh key did not work.

Of course, I did go through this tutorial, which seems to setup a putty session to root user (“Auto-login username” set to root):

https://www.digitalocean.com/community/tutorials/how-to-use-ssh-keys-with-putty-on-digitalocean-droplets-windows-users

I should mention that overall Digital Ocean is great, and the tutorials are very helpful. But in my quest to make my server as secure as possible, these aspects of the tutorials are frustrating.