Fix on Mac for WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!
Use this command to remove this WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! error
ssh-keygen -R your ip address
eg: ssh-keygen -R 45.56.68.191
you get a message like this
Host 45.56.68.191 found: line 11
/Users/Vishnu/.ssh/known_hosts updated.
Original contents retained as /Users/Vishnu/.ssh/known_hosts.old