Hi - is it possible that this article is modified - it doesn't say what to change only what requirements are and a little vague. Just needs direction to modify /etc/ssh/sshd_config and to modify those lines mentioned above e.g.
KexAlgorithms ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
HostKeyAlgorithms ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-256,rsa-sha2-512,ssh-rsa,ssh-dss
Ciphers aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
MACs hmac-sha2-256,hmac-sha2-512,hmac-sha1-96,hmac-sha1,hmac-md5-96,hmac-md5
This adds the right KexAlgorithm, HostKeyAlgorithms and Ciphers
That way, it's more specific to the solution. Thanks !!