Bridge not previewing video thumbnails

When in "View content as thumbnails," image preview of video is not showing- just: a "film strip with Q." Also, "Preview Video on Mouse Hover" is not working. Caches are emptied in Preferences and at start up. 

I need to see a sample of video as a thumbnail otherwise I have to open each video in Quicktime.

Adobe Bridge : 12.0.1.246. ; Mac 10.15.7