Facing Issue in Configuring SSH Access

[akshat-kumar2109]

I had to manually add the SSH keys to each servers. I am getting this error on the following command. Can anyone tell me what can be the reason for this?

root@ip-172-31-19-252:~/kubernetes-the-hard-way# while read IP FQDN HOST SUBNET; do    ssh-copy-id root@${IP}; done < machines.txt
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_ed25519.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@34.232.210.182: Permission denied (publickey).
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_ed25519.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@3.221.163.8: Permission denied (publickey).
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_ed25519.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@3.238.13.255: Permission denied (publickey).

[aasourav]

this works on my local virtual machines. didn't try on cloud.

step 1:
sudo vim /etc/ssh/sshd_config
step 2:
FROM:
#PermitRootLogin prohibit-password
TO:
PermitRootLogin yes

Shortcut (Step 1 + Step 2):
sudo sed -i 's/#PermitRootLogin prohibit-password/PermitRootLogin yes/' /etc/ssh/sshd_config

step 3:
sudo systemctl restart ssh

step 4:
sudo passwd
[sudo] password for linuxconfig:
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

step 5:
sudo ufw allow ssh