I have purchased and logged into Managed DNS, but now need to create a Dynamic DNS Service and Update User.

The Dynamic DNS (DDNS) Service on Managed DNS uses separate credentials from your Managed DNS users. This allows you to securely provide the Update User credentials to end-users without providing them access to your account.

Once the DDNS Service has been established, you can use the Update User in your existing system, or download the Dyn Update Client from https://help.dyn.com/update-clients/.

More on Dynamic DNS:

The following resource was developed for our ecommerce product Dynamic DNS (https://pages.dyn.com/dyndns-remote-access.html), formerly known as DynDNS Pro. However, the underlying principles are much the same and help to describe how DDNS functions: https://help.dyn.com/remote-access/getting-started-with-remote-access/ .

My Dynamic DNS is not updating the IP

The Update User may have been blocked due to too many incorrect logins or too many (abusive) updates. For more information, see https://help.dyn.com/remote-access/why-is-my-hostname-blocked/ .