Thumbnail not showing in post grid

I’m using post grids to pull in category posts, plus the thumbnail image. I have included these features in the layout editor:
– Thumbnail with link
– Post title with link
– Except read more
– share button

They all appear to be populating as expected but the thumbnail is NOT showing. I have each post set with a “featured” image. This did not work. Then updated each post and included a link via the “post grid” options, to the thumbnail in the wp media library. This did not work.

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