Appears to be nothing listening on 443? Apache directives in virtual hosts say "SSL engine on", but I can't see an SSL mod in the apache3 server config under /etc/httpd. Does the SSL system run off the ISPConfig apache server?
The main server logs into ISPConfig as https on port 81, no trouble.
This would suggest SSL is running.
"Those who would give up an essential liberty to purchase a little temporary safety deserve neither liberty nor safety".
Benjamin Franklin 1759