Modify known_hosts
vi ~/.ssh/known_hosts
Find server ip, ip and delete rows can be located, is shown below:
31.241.88.46 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBEp6c2x72plDa4D8OVr+g2HZlHP0O+shHXWLeuflDxaXjX7g/ZCYygr2r3ogiKpTMQeO93PtnHoXht7sspCTQyw=