1: Enable Clipboard history

Right Click on the Start menu and choose Settings

Select System > Clipboard > Make sure Clipboard history is enabled

2: Enable Snip and Sketch

Right Click on the Start menu and choose Settings

Select System > Notifications and actions > Scroll down to "Snip and Sketch and make sure it is turned on.

3: Reset Snip and Sketch

Right Click on the Start menu and choose Settings

Select Apps > Apps and Features > Select "Snip and Sketch" > 

Click on Advanced Options > Scroll down and click on Reset

Taken from:

https://www.thewindowsclub.com/win-shift-s-not-working-windows-10