Could be an authorization issue. Check to make sure you followed the process. From the Izotope site:
AUTHORIZATION iZotope products support three methods of authorization. The method that will be best for you is based on the machine(s) on which you want to install your iZotope products.
If your computer is connected to the internet: The most commonly-used authorization method is Online Authorization, where you can use your serial number to directly authorize a product, after product installation on your machine.
If your computer is not connected to the internet: For offline machines, we offer a Challenge/Response authorization method. For this process, a challenge code is provided by the software on the desired machine after you perform the installation. This challenge code must then be submitted to our website via another web-connected device. A response code or file is then provided that you can use to authorize the offline machine.
If you use an iLok: Our products also support iLok authorization for offline machines, or for users who are using iZotope products on-the-go on a number of different machines.
More about iLok After product installation, the Authorization Wizard will help walk you through the process. Check out the videos below to get step-by-step instructions on the authorization process that’s best for you!