When you originally log into a DreamHost server, you may see the following warning:
The server's host key is unknown. You have no guarantee that the server is the computer you think it is.
To confirm if this is the correct server, navigate to the (Panel > 'Users' > 'SSH Keys') page. On that page, you'll see your server along with its matching Fingerprints.
Compare the two to confirm it's the same server. You can then accept the warning and log in normally.