Ubuntu root@localhost‘s password: Permission denied,please try again.

root@localhost’s password: 密码输入正确，但是一直提示被拒绝，如图：

root@ubuntu:~/.ssh# ssh-copy-id -i ~/.ssh/id_rsa.pub root@ubuntu
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
The authenticity of host 'ubuntu (127.0.1.1)' can't be established.
ECDSA key fingerprint is SHA256:l6Stjl1ZVKPuTmvFA6uLMEeaaUHjR9Dx4xPDLWFqzVQ.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys

root@localhost's password: 
Permission denied, please try again.
root@localhost's password: 
Permission denied, please try again.
root@localhost's password: 
root@localhost: Permission denied (publickey,password).

解决方法：
修ssh改配置文件，设置为允许root远程登录：

root@ubuntu:~# vim /etc/ssh/sshd_config

新增语句：PermitRootLogin yes 即可。

保存退出，重启ssh服务：

root@ubuntu:~# /etc/init.d/ssh restart

再次尝试，成功

root@ubuntu:~/.ssh# ssh-copy-id -i ~/.ssh/id_rsa.pub root@ubuntu
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@ubuntu's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'root@ubuntu'"
and check to make sure that only the key(s) you wanted were added.