If you get this:

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@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @
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The RSA host key for HOST has changed,
and the key for the corresponding IP address IP
is unknown. This could either mean that
DNS SPOOFING is happening or the IP address for the host
and its host key have changed at the same time.
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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 the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
SOME_KEY
Please contact your system administrator.
Add correct host key in /Users/user… to get rid of this message.
Offending key in /Users/user…
RSA host key for HOST has changed and you have requested strict checking.
Host key verification failed.
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Then try:

ssh-keygen -R HOST

And try reconnecting…