Easy to remake /etc/ssh/ssh_host_……key.pub and ssh_host_……key
$ sudo -i # ls /etc/ssh/ssh_host* /etc/ssh/ssh_host_ecdsa_key /etc/ssh/ssh_host_ed25519_key.pub /etc/ssh/ssh_host_ecdsa_key.pub /etc/ssh/ssh_host_rsa_key /etc/ssh/ssh_host_ed25519_key /etc/ssh/ssh_host_rsa_key.pub
if you want to keep old keys;
# mkdir /root/keys/old <--- make directory your choice. # mv /etc/ssh/ssh_host* /root/keys/old
if do not need old keys;
# rm /etc/ssh/ssh_host*
And them make new keys
# dpkg-reconfigure openssh-server
That’s all !