I came across this issue when I was switching around the IP address of this website (sethciasulli.com) and accessing it via terminal on two different servers. When I switched the IP address and then tried to access the newly assigned server I get this error, warning me that the ECDSA Host Key has changed and there could be someone spoofing around my server. It's not someone else, it's me lol. So I searched around and found that this command in terminal erases the host key and lets me sign in again.
ssh-keygen -R (ip address or url)
So now, I can continue along with my coding.