can't ssh into remote host with root, password incorrect

Do you have ssh as root disabled? Check your sshd configuration (possibly /etc/ssh/sshd_config) and look for the line PermitRootLogin no. Change the no to yes and restart sshd (most likely either service ssh restart or service sshd restart).

Some distributions (e.g., Ubuntu) default to without-password for PermitRootLogin such that root login is allowed via public key authentication, but not with a password.

For first time if you are access SSH remote server in new system, just update it. Open the ssh configuration file,

# vim /etc/ssh/sshd_config

PermitRootLogin without-password

change to

PermitRootLogin yes

Restart your ssh service.

restart ssh server.