Find out own SSH fingerprint:
ssh-keygen -lf /etc/ssh/ssh_host_ecdsa_key.pub
Add own public key to remote server for later verification:
ssh-copy-id -i ~/.ssh/id_rsa.pub me@example.com
# then type in password
fix Failed to add the host to the list of known hosts (/home/me/.ssh/known_hosts).
chmod 600 /home/me/.ssh/known_hosts