I have the same problem after I installed Windows 11 as an upgrade from Windows 10. Weirdly at first what I was seeing as Snipping Tool was the old program interface that said a new Snipping Tool would be available in the near future. However, the Windows logo key + Shift + S combination did not work with it although it used to work with Windows 10. After the upgrade I finished installing a couple of Windows 11 updates. Then (after a couple of necessary restarts) the new Snipping Tool interface appeared in place of the old one, but again the Windows logo key + Shift + S doesn't work with it. I get the same message as has been posted here.
I considered installing Screenshot Captor from
For Software Connoisseurs - Homepage - DonationCoder.com, but in the end I decided to leave things as they are and I'll be using the screenshot feature of FastStone Viewer which I already have installed. I rarely use screenshot captures and I didn't feel it necessary to have a special program for them.
EDIT: I finally installed Screenshot Captor, not really because I needed all its features, but hey... I was tempted.