On our Debian Jessie servers, when we run a Webmin update, everything installs correctly but webmin stops responding after the install - I have to SSH into the server and run
/etc/init.d/webmin start
We don’t seem to have this problem with our older Debian servers.
I had just updated to webmin to 1.8, and was unable to login to Control panel remotely. I had to start webmin manually also then I was able to sign in remotely.