On occasion, webmin might not start back up properly, and you might need to restart it. If you are able to shell into your server, it is very easy to bring up the service fresh again using command line.

With root privileges, run the following command:

/etc/init.d/webmin restart

Once you have done this,  you should see something like this below:

Starting Webmin server in /usr/libexec/webmin
Pre-loaded WebminCore

Now go and check and voila your webmin should be running!