I'm sorry you are seeing this problem. Can you please email help@schrodinger.com, our technical support will take you through some steps to determine why you are having this license issue.
I know it is already quite late but I could solve the problem and wanted to share it for the future, as I could not find anything on the internet. If you have installed the license correctly and the license check in the Schrödinger Power Shell is all fine (command: licadmin CHECK), then the only problem is the installation folder which must be set in KNIME. By clicking on File>Preferences>KNIME> Schrödinger, you should select the installation folder. In my case it was the usual folder where all programs are installed (C:\Program Files\Schrodinger2021-2 in Windows). Doing this solved the problem for me, I hope it can help someone else!