#TIL 12 - Fix the SSH issue with droplet on Digital Ocean
I have sent an email to Digital Ocean for support but not much help for me. Luckly, I found out the way after reading a comment from the community question.
sudo nano /etc/ssh/sshd_config PermitRootLogin prohibit-password to PermitRootLogin yes PasswordAuthentication no to PasswordAuthentication yes
then, restart ssh service:
sudo service ssh restart