Dns server not updating
It discusses how DNS propagation works for a newly registered domain, but does not mention if there are any differences between that and just adding a subdomain. You could simply set your domain to the correct name server, and then that correct value would begin to propagate around the web at that point.However if some servers already got the update for your domain pointing at the wrong name server, they will continue to point to the incorrect server and won't default back to the correct value until you update it and fix it.Changing the timeouts is only going to help clients the next time they check in, which is usually after half the existing lease time, or sometimes during boot.You can approach this by manually forcing the clients to check in. It might be easier to drop your scope lease time really low, then delete all the dynamic DNS records and let them get re-created.
If you're an In Motion customer, we have an article that explains how to change your DNS.
Both were clearly using a different terminology or a different understanding of the situation.
As a "bear of little brain" myself, I'm just glad it was resolved without my intervention (apart from the fact that I reinstalled my system in hopes that it would solve the issue - obviously that had no effect, because the problem was server-side! The tech folk on the host and internet providers should perhaps have pointed me to your page here!
You can always check where your domain is pointing by the following domain routing tool.
Visual Domain Routing Tool You can also ping and trace route your domain locally from your Windows/Mac command prompt to verify what IP you are actually seeing.The cache is cleared over a certain amount of time.