We have got this message below when trying to connect via SSH. WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!
The instructions @ericklan posted are on the right track, though they aren't quite clear to me and seem to recommend more than is necessary....
Change key Super that launches dash in Ubuntu First, disable the "Cmd" button, which likely corresponds to the Super (also known as Windows) key on other systems. This can be achieved with the gsettings terminal command: