when have opened a Remote Desktop Connection it sometimes happened that the clipboard stops working.
When you closing and reestablish the Remote Desktop Connection the clipboard functionally comes back.
But its also possible without closing the RDP Session:
to generate sshd host keys, for example in case of cloning a virtual linux instance, do the following steps:
Checkout the key file names
root@debdevt:~# grep HostKey /etc/ssh/sshd_config
# HostKeys for protocol version 2