Make sure you copy/paste your license key details into PerfectIt. Please do not attempt to type them out.
If you have copied/pasted the details, and they still don't work, this usually indicates that you're entering the details for the wrong version. For example, PerfectIt 2 licenses won't work in PerfectIt 1. So to make sure you are using the most up-to-date license that you purchased, retrieve your license details here.
If your license still doesn't work, you may be running a version of PerfectIt that is older than your license. Download and install the latest version.
If that still doesn't work, please take a screenshot so we can see the full screen and the error you get. To do that, press the 'Prt Sc' key on your keyboard. That copies a picture of the screen to your clipboard. You can then paste that into an email or document and send it to us.