Problem: Unable to SSH into a digitalocean droplet due to error, "Access denied (publickey)" even after uploading public key during configuration.
1. Login as root to your server via digitalocean's console utility
2. Edit the contents of /etc/ssh/sshd_config (eg. nano /etc/ssh/sshd_config)
3. Find and change the value next to PasswordAuthentication from no to yes, and remove any preceding pound sign (#)
4. Save the file and then reload the SSH service (service sshd reload)
5. Run the following from your LOCAL device: ssh-copy-id user@ipaddress
6. Change PasswordAuthentication back to no if you don't want to be prompted for a password when you login (and don't forget to reload the service)
Note: The ssh-copy-id command assumes your keys are located in ~/.ssh and named exactly id_rsa.pub - otherwise use: ssh-copy-id -i /dir/mykey user@ipaddress