Hello All,
I had the same issue when I created my lab environment. Peter_dyer123 is absolutely right and what the KB does not mention is that an Active Directory DNS out of the box does not create a reverse lookup zone. It is not needed to run AD but some applications (like VCSA) need it. No reverse lookup means no PTR record. Do not create a PTR in the forward lookup DNS zone, that is bad form.
Create a reverse lookup using this link:
once you have done that you'll need to specify your NetworkID (during zone creation). For basic installs, this is the same subnet that your AD\DNS is in. (NOT subnet mask)
Once completed you may need to manually add the PTR record of your Active Directory server into the reverse lookup zone. In theory you shouldn't BUT I needed to do this to get it working.
Let me know if helps others.
-Ryan