Host Identification has changed for no obvious reason

This is the error I'm getting when I tried login in to my server

 ssh [email protected]
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@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
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IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:nLdtZYZ3MPLkpSPFJWFEO0bn8/mlG3Oe0NtEYdKbcNU.
Please contact your system administrator.
Add correct host key in /home/abayomi/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /home/abayomi/.ssh/known_hosts:3
  remove with:
  ssh-keygen -f "/home/abayomi/.ssh/known_hosts" -R "143.110.229.222"
ECDSA host key for 143.110.229.222 has changed and you have requested strict checking.
Host key verification failed.

OK I just successfully removed the previous hostname, I then tried to do this ssh 143.198.104.166 I'm now getting this error [email protected]: Permission denied (publickey). my user no longer has access to login to the server.

1. ssh Secure Shell - is a program for logging into a remote machine and for executing commands on a remote machine.
2. To connect remote server you have to install "ssh server" Secure Shell Daemon - sshd.
3. sshd usually listen to port 22 and you can connect the ssh server by using the command ssh username@hostname
4. You can change your ssh server configuration by editing the configuration file /etc/ssh/sshd_config
5. To your specific question:
   • The known_hosts problem may cause because you're using the same remote computer address as before but the remote computer is responding with a different fingerprint.
   • Therefore as i commented the command ssh-keygen -f "/home/abayomi/.ssh/known_hosts" -R "143.110.229.222" will solve the warning message problem.
   • The "permission deniend" error caused because you do not have keys to the specific server.
   • To add more keys to ssh server you have to add your public key to the authorized_keys file which located on /home/username/.ssh/authorized_keys or in the root user /root/.ssh/authorized_keys.
   • To generate new keys you can use the ssh-keygen command.