I just had this same problem. I created the droplet using DO’s ‘One-Click apps’ with Ghost 1.2.11 on Ubuntu 16.04. By default, Ghost installs using the IP address as the domain name. If you try and simply point your DNS to your droplet and then go to your domain, you’ll get the blue screen with the shark and “Please log into your droplet via SSH to configure your Ghost installation”.
Here’s how I fixed it -
First of all, I enabled backups on my droplet. I highly recommend it. It’s cheap, and it’s worth it x100. When I got to this screen, I started tinkering and got to the point where I wanted to go the route of @paulcimino and just start over. But I figured I would give it a shot first. So I restored my droplet to my earliest backup and removed the DNS for my domain.
Then, I SSH’d into the droplet as root and ran
vim /etc/nginx/sites-available IP_ADDRESS.conf
Change server_name IP_ADDRESS to server_name domain.com
Then run
vim /var/www/ghost/system/files IP_ADDRESS.conf
Change server_name IP_ADDRESS to server_name domain.com
Then run
service nginx restart