That should be ok then, there is no need that you can reach a website, it's enough to reach the apache default vhost. Strange that it fails then ...
Are you still on 3.2.2? If so, try updating to 3.2.3, reconfigure services and select to create ssl during the process, again.
I'm on ISPConfig Version: 3.2.3 And I've reconfigured services several times, using: Code: ispconfig_update.sh --force But I have this issue on all my Ispconfig servers (about 7), don't matter if Debian 9 or 10, nor Ispconfig 3.1.x or 3.2.x By the way, my servers have not dns server component enabled, but I don't think it would be an issue here, if my domain has A records... Maybe, because I remember some read about it, could be an issue related with IPV6? I'm not using IPV6, but not sure if /etc/hosts config file, or any other setting, could seem I have this enabled. Because I've read that if acme/certbot guess you are using ipv6, it try to check it, and if not really in use, certification fail... Here my /etc/hosts
ISPConfig should work with either or both, so I don't think not setting ipv6 is a problem, since other web sites in that server also work.
Just to let you know: I just ran into the same problem (ispserver.crt seems to be missing) with Debian 10 using the Perfect Server Setup und I used latest IspConfig 3.2.5. Tills advice 1) Install acme.sh 2) then run ispconfig_update.sh --force still solved the problem