Last week I spend a lot of time installing and re-installing remote Ubuntu servers. Every time was trying to connect with SSH to the server it asked me whether I trusted the server. When you type `yes` (trust the server), your local machine saves the fingerprint of that server. So the next time you don’t have to type `yes` again.
The problem is: after installing a new server the fingerprint changes. When the next time you try to access the server via SSH it fails. Because your local machine does not trust the identity anymore.
To fix it you could run the following command from within your Terminal session:
ssh-keygen -R server.address.com
Replace server.address.com with the address of the server you working with.