We've upgraded Hatchbox to use ed25519 SSH keys by default. SSH RSA is no longer accepted by default in Ubuntu 22.04 and we've adjusted accordingly to support them.
For clusters created before April 2022, we've generated new SSH keys and have added them to your servers. There's nothing you need to do on your end. 🎉
To connect to your servers over SSH, make sure you're using a compatible SSH key for Ubuntu 22.04. If you don't, SSH will refuse the connection.