This error message occurs when WinSCP connects to a new SSH server. Every server identifies itself by means of a host key; once WinSCP knows the host key for a server, it will be able to detect if a malicious attacker redirects your connection to another machine.
If you see this message, it means that WinSCP has not seen this host key before, and has no way of knowing whether it is correct or not. You should attempt to verify the host key by other means, such as asking the machine’s administrator. 1)
Read more about verifying host keys.
Learn also how to accept host key automatically in script.
Site design by Black Gate