Joint Push Pull Plugin Sketchup 2021 - Free Download 'link'
You are trying to use it on a grouped component. Double-click to enter the group, or explode the component first. JPP works on raw faces only.
The plugin offers several specialized tools to handle complex 3D modeling tasks: Joint Push Pull Plugin Sketchup 2021 Free Download
: Extrudes faces along a specific, user-defined direction or axis, which is ideal for flattening terrains or projecting shapes. You are trying to use it on a grouped component

