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@       WARNING: POSSIBLE DNS SPOOFING DETECTED!          @
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The RSA host key for github.com has changed,
and the key for the corresponding IP address 140.82.112.3
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 a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
SHA256:uNiVztksCsDhcc0u9e8BujQXVUpKZIDTMczCvj3tD2s.
Please contact your system administrator.
Add correct host key in /home/ubuntu/.ssh/known_hosts to get rid of this message.
Offending RSA key in /home/ubuntu/.ssh/known_hosts:1
  remove with:
  ssh-keygen -f "/home/ubuntu/.ssh/known_hosts" -R "github.com"
RSA host key for github.com has changed and you have requested strict checking.
Host key verification failed