Too many Authentication Failures for user root

"Too many Authentication Failures for user root"
This means that Your SSH server's MaxAuthTries limit was exceeded. It happens so that Your client is trying to authenticate with all possible keys stored in /home/USER/.ssh/ .

This situation can be solved by these ways:

1. ssh -i /path/to/id_rsa root@host

2. Specify Host/IdentityFile pair in /home/USER/.ssh/config .
Host host
IdentityFile /home/USER/.ssh/id_rsa