Hi @Manikandan_R,
I believe that you don’t return a thumbnail because in your URL you have shorts! If you add this URL on a video component you will not see the video too.
But you can format the URL with a template column and add that Template column on the YouTube Thumbnail column! Check here : Support for YouTube Shorts in the Video component - #2 by Dilon_Perera
Also made a video : YouTube Video Thumbnail.mp4 - Google Drive
Hope this helps!
Thank you