RSA host key changed, requires validation: what to do
RSA host key for example.com has changed and you have requested strict checking.
Host key verification failed.
In the line above it will actually tell you where the bad key is, with known_hosts being the file and 2 being the position of the problem key:
Offending key in /home/you/.ssh/known_hosts:2
After verifying that the RSA host key has changed and the new fingerprint is correct (the point of this alerting and blocking you is to protect you from a man-in-the-middle attack), you can get past this block and log into the server by deleting the old key, on your local computer of course:
Ebony-II:~ you$ sudo vi .ssh/known_hosts