xxx:/etc/logrotate.d# ls /etc/webmin
e5d488f2.0 miniserv.pem miniserv.users
-----------------------------------------
Any recommendation of what can be wrong? My understanding that this
error has something to do with openssh.
It doesn't seem that anything is wrong. As part of the post-installation
script, webmin looks to see if you already have a miniserv ssl certificate
and creates it if you don't.
If you want to be absolutely sure the package is properly installed, do
dpkg -l webmin
If the first two letters on the line are ii, you are ok.