First of all, I am not sure whether we're using ISPConfig 2 or 3, and I don't know if that's relevant ...
When I tried to access ISPConfig today, I got a message about the certificate being expired, etc., so I did a Google search on how to update the ISPConfig certificate, and I got this:
I followed the instructions under "You can re-generate the ISPConfig SSL certificate like this:", inserting our root password in place of "yourpassword", then I restarted ISPConfig ... but now the admin interface is entirely inaccessible ("Unable to connect" error in Firefox). When I restart ISPConfig again, it says:
Shutting down ISPConfig system...
/root/ispconfig/httpd/bin/apachectl stop: httpd (pid 9682?) not running
ISPConfig system stopped!
Starting ISPConfig system...
/root/ispconfig/httpd/bin/apachectl startssl: httpd started