The host key sent by the remote host computer did not match the key stored by the client.
A change in the host identification may be caused by one of the following reasons:
The administrator of the remote host computer has changed the host key.
The administrator of the remote host computer has changed the IP address (or the host name) of the remote host.
An intruder is trying to pose as the remote host computer.
If you encounter this situation, do not proceed with the connection. Contact the system administrator of the remote host computer (preferably by phone) and check the reason for the failed identification. Only proceed with the connection when you are sure that the error is not caused by an intruder.