Well over 70 percent of all support calls that come to Microsoft support services that start out as Active Directory or Exchange calls end up being DNS calls.
Likewise, if the server is receiving the update but the record is still not getting updated then it might be a dns Node object permission problem. If you need help, this Technet article is a great resource we'd recommend for understanding the entire workflow from client to server.
There are a few other settings that must be correct on each client as well.
Here's a Power Shell script that lets you easily test for multiple different problem scenarios. Ensure dynamic updates are enabled on the DNS zone This is less likely to be the problem because all clients would not be working is the dynamic updates setting on the DNS zone. If set to Secure, you may begin to see more instances like the ones we'll be talking about in #4 below. Check permissions on the dns Node AD object This problem in particular was extremely hard for us to track down on one occasion.
Imagine if an important server's DNS A record suddenly gets changed to the wrong IP. DDNS can sometimes go on a walkabout and it's important to know where to start troubleshooting if this happens.
Let's demonstrate a typical troubleshooting scenario that you may come across with DDNS.