If you are evaluating PDFTron products, and you get an error stating that you need a valid key, then you need to request a demo license key. Once you have the demo key you add it to your
If you have purchased a license key from PDFTron, then you would pass it into your call to
PDFNet.Initialize or into your WebViewer constructor. You should have received more detail instructions in the email that sent you the purchased license key.