If the fingerprint of your remote host changes you will see the following error message appear:
~ % ssh -i "mykey.pem" user_id@host.af-south-1.compute.amazonaws.com
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
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 ED25519 key sent by the remote host is
SHA256:S60CvpE17ri+E594StxXBQcNIrga4Nb7uX4s7BPr3dw.
Please contact your system administrator.
Add correct host key in /Users/user_id/.ssh/known_hosts to get rid of this message.
Offending ED25519 key in /Users/user_id/.ssh/known_hosts:2
Host key for my_host.af-south-1.compute.amazonaws.com has changed and you have requested strict checking.
Host key verification failed.There are many ways to fix this. The easiest of which is simply to delete your “known_hosts” file. This will mean you just need to accept new finger prints on all your SSH hosts. Yes, this is very lazy…
rm ~/.ssh/known_hosts