I _did_ set myself up as a client as well, but that was simply so it was easier for me to keep track of non-customer sites. It's a personal choice.
you do need to add a client for your own websites if you have enabled the domain limits module, it won't let you had a domain into the domain list without specifying which client to assign that domain to.
so why then does xyz.tld or www.xyz.tld show the default apache is working page? Target goal is to have a site for ourselves main site that can list say "hosting services and prices" and also maybe a page for current events in the local community things like that.. And thanks for the help.
using just http? or using https? most likely the site doesn't have a valid certificate. another possibility, you created a website using the same name the ispconfig panel / server uses for itself. a third option, there's a problem with the initial vhost config so it wasn't enabled when apache/nginx restarted.
Also see read before posting, chapter 2: https://forum.howtoforge.com/threads/please-read-before-posting.58408/
Now things are beginning to make some sense. Let me absorb this till I work out some of this on a VM. Then when the cobwebs in my head clear. I will move to live test server before a follow up on this thread. Learning that what if does not a good linux user make . Can not upload image, so my idea of a a future.