Too many authentication failures for root
If you get the following error, the most reason is, that you have to many ssh keys.
“Received disconnect from 172.23.23.23: 2: Too many authentication failures for root”
This is easy to fix for password authentication
ssh -o PubkeyAuthentication=no email@example.com
This is easy to fix for a other key
ssh -i .ssh/keyfile firstname.lastname@example.org
If you have a problem to login per ssh and key in the server you must check the auth.log file to see more detail.
Authentication refused: bad ownership or modes for directory /home/user/.ssh
When you see this message you have a problem with the permission of .ssh/authorized_keys
chmod 600 .ssh/authorized_keys
chmod 700 .ssh/
to your sshd_config file you can also fix the problem, but thats not a good idea. Fixing the permission is the best way.