I restored my droplet to downgrade from 16.04 to 14.04. Ever since, my SSH keys are not working. I tried removing and recreating without success. I manually added the same new key on my local machine, my droplet, a...
I would first check SSH config, it could be that somehow is wrong there and it's ignoring keys.
Open config file with you favorite editor:
sudo nano /etc/ssh/sshd_config
Now verify that following settings...