Fix REMOTE HOST IDENTIFICATION HAS CHANGED warning with ssh-keygen -R

When SSH shows this warning:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ 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.

your local known_hosts entry for that host no longer matches the server key.

Quick fix

Remove the stale host key entry, then reconnect:

ssh-keygen -R github.com

Or for a custom host/IP:

ssh-keygen -R <hostname-or-ip>

After that, connect again:

ssh -T git@github.com

SSH will prompt you to trust and save the new host key.

Notes

• This often happens after server rebuilds, host key rotation, or DNS/IP changes.
• Do not ignore this warning blindly for unknown hosts. Verify the fingerprint from a trusted source first.