Knockout Option in Advanced Blending Not Working

Hi Priy,

Thanks for including your screen shot. It clearly shows the issue. A shallow knockout will punch through the layers in a group, and stop at the first layer below the group. If you want to achieve your desired result, put the polygons in a group, and have the yellow solid color layer be the first layer under the group:

Also, I wonder if you have set the Fill opacity to 0% for your knockout layer?

Can you explain in more detail what it is that is not working? Can you show us a screen shot including your layers panel?

See this help page for details on how to use the knockout feature:

https://helpx.adobe.com/photoshop/using/knockout-reveal-content-layers.html