Subdomain - Domain mapping

Hi!

We recently started using your multisite solution. We've used some other solutions before but your setup looked good so we decided to check it out.
This multisite will exclusively be subdomains.

During the mapping of the domain it says that the domain is unavailable to access and that we need to create a CNAME for the subdomain?
An A-pointer for the subdomain is pointing to the server.
We don't have access to the DNS settings.

Is there a solution were an a-pointer to the subdomain is sufficient?
If there isn't, we unfortunately have to switch multisite solution. :disappointed: