You cannot create an addon domain if the DNS for the site you are trying to add is yet to propagate.
Addon domains are handled similarly to subdomains in terms of the file structure listed in your file directory; however, the addon domain URL appears like a primary domain. In general, nothing that happens in your addon domain's files or DNS should affect what goes on with the rest of your domains.
Although addon domains do not have their own cPanel, you may still create email accounts, redirect, Softaculous installations, subdomains, etc.
Web statistics for the addon domain can be found under the subdomain's URL in the statistics application in cPanel.
