ssh Unable to negotiate with 22.214.171.124 port 22: no matching host key type found. Their offer: ssh-dss
Unable to negotiate with 126.96.36.199 port 22: no matching host key type found. Their offer: ssh-dss
The version of OpenSSH included in 16.04 disables ssh-dss. There’s a neat page with legacy information that includes this issue: http://www.openssh.com/legacy.html In a nutshell, you should add the option -oHostKeyAlgorithms=+ssh-dss to the SSH command:
ssh -oHostKeyAlgorithms=+ssh-dss email@example.com
➜ ~ ssh -oHostKeyAlgorithms=+ssh-dss firstname.lastname@example.org The authenticity of host '188.8.131.52 (184.108.40.206)' can't be established. DSA key fingerprint is SHA256:LVWhbgb8q5TdW2QEsFjOVNp8ekW8UqPVE/KCbMOI4CM. Are you sure you want to continue connecting (yes/no)?